texts: How is Precise Point Positioning (PPP) exactly done?

texts:
I am looking for a positioning accuracy that is higher than normal consumer-grade GNSS receiver (mostly GPS/GLONASS hybrids with +- 5m precision). I came across RTK with dual receiver setup (base station + rover) which is supposed to do cm-level precision although it has the "disadvantage" while it needs a base station or another source of correction data that one may not be able to supply.

I am interested in getting the most of a single receiver setup. I read Precise Point Positioning (PPP) is able to achieve sub-meter (or maybe even 20cm-level) accuracy. I think PPP needs raw data from sensor which I can do. I will do readings from a moving vehicle in my application so I can not go with stationary "averaging" over time for getting the accuracy. However, I do not need a real-time solution as I will only collect mobile data and evaluate it later so I can do positioning in post-processing.

U-blox also has a page on PPP where I get the impression their solution is just an ordinary raw data chip with a "better firmware" that can do some additional calculations (quote: "... by stabilizing measurements of the distance between GNSS satellites and the receiver (pseudo-ranges) using carrier phase tracking") so it has better precision than ordinary chip.

I read the Wikipedia article but I do not really understand how PPP works. So how exactly is this PPP correction technically done? Where do the corrections come from?

I read RTKLIB can do PPP too. My location is Czech Republic.


texts: fiona ValueError: invalid literal for int() with base 10: 'str'

texts:
Why below code does not work-

import fiona
from fiona.crs import from_epsg

my_schema = {'geometry': 'Point', 'properties': {'mean_in': 'str', 'total_h1': 'str', 'total_h2': 'str', 'LOS': 'str', 'id': 'str', 'index': 'str', 'Junctio': 'str', 'intLanes': ':str', 'flow': 'str', 'incLanes': 'str', 'interva1': 'str', 'y': 'str', 'x': 'str', 'entered': 'str', 'type': 'str', 'Incomin': 'str', 'interva2': 'str'}}
wr_dict = {'geometry': {'type': 'Point', 'coordinates': (488901.97760411515, 5078198.250875515)}, 'properties': {'mean_in': '0', 'index': '0', 'Junctio': '0', 'intLanes': ':A_0_0 :A_1_0', 'flow': '0', 'total_h1': '0', 'total_h2': '0', 'LOS': '0', 'incLanes': 'B-A_0 A0-A_0', 'interva1': '0', 'y': '39.18', 'x': '31.72', 'entered': '0', 'type': 'unregulated', 'id': 'A', 'Incomin': '0', 'interva2': '0'}}

with fiona.open("my_shp_clean1.shp", mode='w', driver='ESRI Shapefile', schema=my_schema,crs =from_epsg(32632)) as output:
    output.write(wr_dict)

Rather raises exception as below-

  File "C:\Python27\ArcGIS10.3\Lib\site-packages\fiona__init__.py",
  line 183, in open   enabled_drivers=enabled_drivers, crs_wkt=crs_wkt)
  File "C:\Python27\ArcGIS10.3\Lib\site-packages\fiona\collection.py",
  line 161, in init   self.session.start(self, **kwargs) File
  "C:\Python27\ArcGIS10.3\Lib\site-packages\fiona\ogrext.pyd", line 890,
  in fiona.ogrext.WritingSession.start (fiona/ogrext.c:15383)

  ValueError: invalid literal for int() with base 10: 'str'

N.B. I am with Fiona (1.6.2),Shapely (1.5.13),GDAL (1.11.3) and python 2.7 in windows 8


texts: Installing both ArcGIS for Desktop and Python(x,y) on same machine?

texts:
I'm trying to get ArcGIS 10.1 and Python(x,y) to peacefully co-exist with a unified installation of Python. Surely someone else is using both these tools... right?

Here's where I've gotten to:

VERSION: Since ArcGIS 10.1 uses Python 2.7.2 (which contains NumPy 1.6.1), I went back to the pythonxy install mirrors and found version 2.7.2.0 of Python(x,y) which includes Python 2.7.2 and NumPy 1.6.1.
INSTALL: I crossed my fingers and just installed Python(x,y) after copying my original "C:\Python27\ArcGIS10.1\" folder to a safe location. It installs most of the files at "C:\Program Files (x86)\pythonxy\", and the Python files in "C:\Python27\". This is the same folder where my Arc install of Python lives, except Arc placed its version in the sub-folder "\ArcGIS10.1\". So to recap, I now have a "python.exe" and associated files in "C:\Python27\" as well as "C:\Python27\ArcGIS10.1\".
NEXT? Both Spyder and ArcGIS 10.1 seem to work so far but I'm guessing this won't last long. Two separate installs on the same machine seems like a bad move in principle. I wonder: Is it possible to change Arc's preferences to point to the version in the parent folder, and condense versions? I've gone through folder by folder and in almost every case the Python(x,y) install includes all the files that ArcGIS 10.1 Python does (and then some). The exception is that the Arc install sometimes includes '.pyc' and '.pyo' versions of some '.py' files. But I'm guessing this isn't a critical difference since both directories contain the actual '.py' file.)
Forgot to mention: I added "C:\Python27\ArcGIS10.0\" to the list of system paths, per the instructions in Method 2 at http://forums.arcgis.com/threads/34418-is-it-possible-to-install-other-python-distributions-on-top-of-the-arcgis. I really don't know what this does, just experimenting here.

I may post the same question at forums.arcgis.com, so if interested in the answer check there too.

I tried to add 'python(x,y)' as  a tag but was unable to create a new tag.


texts: How to join information from an excel table to a road feature in QGIS?

texts: I'm working with GQIS 2.2.0 Valmiera. I've made a shapefile of a road that consists in a single line. Now I want to add information that I have in an excel table about several point in the road. How can I join this informations?


texts: Using IFeature Selection with ArcObjects and C#?

texts:
I have a list of IFeature (List lst) and I want to select and highlight and show in the map. All I am getting is like the IFeatureSelection , ISelectionSet and they work with Feature Layer not the feature. Can anyone show me some light in that direction. Regarding the context, I am getting the features from a method  after validations  and I am trying to select those/ or highlight those.

public void HighlightInvalidFeatures(List<IFeature> featureList, IActiveView activeView, IGeometry geometry , IMap map)
        {
            //First find all the feature classes that exist for your features
            Dictionary<IFeatureClass, List<int>> uniqueFeatureClasses = new Dictionary<IFeatureClass, List<int>>();
            IFeatureClass fc = null;
            foreach (var feature in featureList)
            {
                fc = feature.Table as IFeatureClass;

                if (!uniqueFeatureClasses.ContainsKey(fc))
                    uniqueFeatureClasses.Add(fc, new List<int>());

                uniqueFeatureClasses[fc].Add(feature.OID);
            }

            //get the current map object
            IMap mapInstance = map;

            //clear the current selection
            mapInstance.ClearSelection();

            IFeatureLayer fLayer = null;

            IQueryFilter filter = null;
            //create and add the layers
            foreach (var pair in uniqueFeatureClasses)
            {
                //create the FeatureLayer
                fLayer = new FeatureLayerClass();
                fLayer.FeatureClass = pair.Key;
                fLayer.Name = pair.Key.AliasName; //this could be anything

         IEnumLayer enumLayer = mapInstance.get_Layers(null, true);
                 ILayer esriLayer = null;
                 while ((esriLayer=enumLayer.Next()) != null)
                {
                     // Check this if part
                        if (esriLayer.Valid)
                        {
                                if (esriLayer == featureLayer)
                                {
                        fLayer = esriLayer;

                                }
                    else
                    {
                        // Adding the layer
                        mapInstance.AddLayer(fLayer as ILayer);
                    }
                        }
                }

                //select on the layer
                filter = new QueryFilter();
                filter.WhereClause = pair.Key.OIDFieldName + " IN (" + String.Join(",", pair.Value) + ")";

                // filter.WhereClause = fc.OIDFieldName + " IN (" + String.Join(",", pair.Value) + ")";

                activeView.PartialRefresh(esriViewDrawPhase.esriViewGeoSelection, activeView.FocusMap, null);

                (fLayer as IFeatureSelection).SelectFeatures(filter, esriSelectionResultEnum.esriSelectionResultAdd, false);

                activeView.PartialRefresh(esriViewDrawPhase.esriViewGeoSelection, activeView.FocusMap, null);
            }

        }
        #endregion
    }


texts: Is it any way to make layer list collapsible in newest QField? Or can I change project settings the way legend contains only list of layers without symbology variants? Because now I have almost infinite scroll in my QField project with all layers and its variants.


texts: How to add a projection to a Shapefile using open-source tools?

texts:
I have been given some shapefiles WITHOUT a projection.  So I need to add the projection in order to display it on google map.  I found the projection information I need at http://spatialreference.org/ref/epsg/2066.

Question:
How can I add the projection using an open source method (don't have access to ESRI's software)?

Thanks
Chris


texts: How to get the Shape.STLength() value from JSON

texts:
I'm trying to get the Shape.STLength() value from a feature returned from a query.

something like

var myLength = returnedJSON.features[0].attributes.Shape.STLength();

"Shape.STLength()" is actually an attribute name but I'm guessing that the way I have it in my code is making it look like parts of the JSON object. And the () is making javascript think it is a method.

How do I pass the name as a string? I tried messing about with enclosing it with "" but can't get it to work.


texts: Drawing/putting pushpin in QGIS map layer for specific lat/long or NGR?

texts:
How do I draw/put a pushpin in QGIS map layer for a specific lat/long or NGR?

In MapInfo it is quite easy but just wanted to learn how to do the same in QGIS. I have version 3.8.3.


texts: Nearest Neighbor Analysis for route events

texts:
I have events that are on routes. You can think of it as accidents on a highway. I want to do some spatial statistics on it. The road is an M enabled feature class and decision makers want logical distances first.

Is it considered to be a single dimension? What tool in ArcGIS can I use to calculate something like Average Nearest Neighbor?


texts: Combining four shaded relief images into one single image using GIS overlay technique?

texts:
I have prepared four shaded relief images (hillshade) with four contrasting illumination directions 0°, 45°, 90° and 135°.

I would like to combine four shaded relief images to produce one shaded relief image with multi - illumination directions (0°,45°,90°,and 135°) for lineament analysis.

How could I combine these four shaded relief images using GIS overlay technique in ArcMap 10.1?

Kindly give me step-wise suggestions.


texts: How can I zoom to extenct according for dynamic WMS (coming from DB)?

texts:
I have a WMS layer that is coming from SQL View.
I want to be able to zoom to extent of layer when clicking a button (view changes because data keep coming to the DB).

How can I get the rectangle that currently contains the points and zoom to it ? (or an alternative is to make a polyline from the points and zoomtoexctent of it.. but its kinda overkill I think)


texts: How to cut out a small section in my shapefile?

texts:
I have a shapefile of a whole region. Since every change I do require a lot of loading time, I would like to cut out one small section which I actually need and create a new shapefile - the rest I could delete. Is it possible to cut out a square and save it as a new, smaller shapefile?

I have seen the “Clipper” – Tool, but for that  I thought that I need another shapefile or a map so that I can lay them together… I need something very simple (like for example the same principle of the drawing program “Paint” – I hope you know what I mean).

I am using the QGIS 2.12.3 - Lyon Version.


texts: Improve GeoServer WMS tile loading delay

texts:
I'm using OpenLayers 2.13 and GeoServer 2.3.5 for my development.
Following code is I'm using for loading map tiles..

map.addLayer(new OpenLayers.Layer.WMS(
    "LoadedLayers",
    url,
    {
        width: '1062',
        height: '286',
        srs: 'EPSG:3857',
        layers: multipleLayers,
        styles: '',
        format: 'image/png',
        bgcolor: '0x80BDE3'
     },
     {
        singleTile: true,
        //tiled: true,
        //tilesOrigin : map.maxExtent.left + ',' + map.maxExtent.bottom,
        ratio: 1,
        visibility: true,
        isBaseLayer: true
    }
);

While using SingleTile:true option map is taking around 10 to 15 seconds to load the tiles.Here only single wms request is going to server.

Then I have tried to use like below

tiled: true,
tilesOrigin : map.maxExtent.left + ',' + map.maxExtent.bottom,

But, here also its taking around 10 seconds to load map complete tiles.And the width: and height: of the tile is changed to 256. And here around 20 to 24 request is going to server.

Can we change the width and height in tiled:true option.? or is there any other method to improve wms tile loading delay using limited wms request.

Sample Single Tile GeoServer request url:

localhost:7080/geoserver/wms?LAYERS=layer%3Alanduse_district_border%2Clayer%3Alanduse_city_border%2Clayer%3Alanduse_builtup_area%2Clayer%3Alanduse_park%2Clayer%3Alanduse_lake%2Clayer%3Arailway_line%2Clayer%3Apoi_railway_station%2Clayer%3Aroad_colony%2Clayer%3Aroad_minor%2Clayer%3Aroad_major%2Clayer%3Alocation_placename%2Clayer%3Alocation_major_placename%2Clayer%3Alocation_major_cityname%2Clayer%3Apoi_bus_stand%2Clayer%3Apoi_hotel_restaurant%2Clayer%3Apoi_hospital%2Clayer%3Apoi_airport%2Clayer%3Apoi_police_station&WIDTH=1062&HEIGHT=286&STYLES=&FORMAT=image%2Fpng&BGCOLOR=0x80BDE3&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&SRS=EPSG%3A4326&BBOX=77.123507022705,28.607589532471,77.305811405029,28.656684686279

Sample Single Tile GeoServer request url:

localhost:7080/geoserver/wms?LAYERS=layer%3Alanduse_district_border%2Clayer%3Alanduse_city_border%2Clayer%3Alanduse_builtup_area%2Clayer%3Alanduse_park%2Clayer%3Alanduse_lake%2Clayer%3Arailway_line%2Clayer%3Apoi_railway_station%2Clayer%3Aroad_colony%2Clayer%3Aroad_minor%2Clayer%3Aroad_major%2Clayer%3Alocation_placename%2Clayer%3Alocation_major_placename%2Clayer%3Alocation_major_cityname%2Clayer%3Apoi_bus_stand%2Clayer%3Apoi_hotel_restaurant%2Clayer%3Apoi_hospital%2Clayer%3Apoi_airport%2Clayer%3Apoi_police_station&WIDTH=256&HEIGHT=256&STYLES=&FORMAT=image%2Fpng&BGCOLOR=0x80BDE3&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&SRS=EPSG%3A4326&BBOX=77.16796875,28.65234375,77.2119140625,28.6962890625


texts: Open Failed - Attribute Column Not Found

texts:
I'm running a PostgreSQL database on my local machine and have set up an connection to it from ArcMap 10.1.  I can see all of my tables in the Catalog pane.  There is one table that I cannot seem to load into ArcMap.  When I drag it onto the map I get the error "Error Opening Feature Class, Attribute Column Not Found"

Other feature classes in the same database load without incident.  The feature class is a relatively (~40 rows) small with point geometry.  It loads without any problems in QGIS.  Also, I can load the feature class from a query layer using SELECT * FROM [Feature Class].

So what's going on with ArcMap that I can't just load the FC straight in like I can with the other FCs in the database?

I'm running ArcMap 10.1, on a Windows 7 machine, with NO instance of ArcServer, PostgreSQL is running locally.  I have the Postgres client files installed.

Thanks!

---------- EDIT ----------

The table has 14 columns:

The spatial reference is 32613 (WGS 84 NAD 83 Zone 13N) and the permissions are no different than others in the database.
Typically, I just drag the tables in from the Catalog pane to load them into ArcMap - perhaps Arc is building a query layer in the background, I don't know.  However, when I do the drag-and-drop with this error it won't load.  When I create a query layer using the "Add Query Layer..." dialog from the File menu it at least loads the points, however, I can't do any kind of selecting and the attribute table is empty.

An example of the columns for a table that I can simply drag-and-drop:


texts:
A C# web application I'm working on needs to be able to load GeoJSON data and save it as an ESRI shapefile (either for download or to view in the browser). The GeoJSON is stored in a database and retrieved as a string.

The GDAL/OGR site says that the OGR GeoJSON driver accepts data as "text passed directly and encoded in GeoJSON" but doesn't say how to do so and there are no code samples that show how to use it.

How can I load the GeoJSON data from a string into a DataSource (or DataSet) using the GDAL/OGR API so I can export as a shapefile?

Note: I've searched GIS.SE and while GDAL OGR API GeoJSON from other datasource as string NOT file sounds like the same issue it is in fact the reverse, the OP wants to serialize the shapefile's data as GeoJSON.


texts: Raster - pixel values not matching legend

texts:
I am a novice at working with raster data.
I extracted hundreds of .tiff files from a WMS and now I need to run zonal statistics on them using ArcGIS 10.5.1. The original map legend on the website shows rainfall values between 1mm to +3000mm. These are the values I need for my zonal statistics. But the downloaded raster file the pixel values are 0-10 and the colormap has values 1-255.

I've tried stretching, but I'm still getting values up to 255.
What would be the correct process and tools (that I can hopefully run through ModelBuilder or ArcPy) to adjust pixel and classify as shown in the legend?


texts: Error from create a reference to the QgsApplication

texts:
I followed these getting started instructions to create a standalone script in pycharm.

The only thing I did differently was to download the standalone installer, not the network installer.

I'm trying to run this code from pyqgis_developer_cookbook.

from qgis.core import *
QgsApplication.setPrefixPath(r"C:\Program Files\QGIS 3.4\apps\qgis", True)
qgs = QgsApplication([], False)
qgs.initQgis()
qgs.exitQgis()

But when it runs qgs = QgsApplication([], False), an error pops up:

  This application failed to start because no Qt platform plugin could
  be initialized. Reinstalling the application may fix this problem.


texts: How to avoid field map change when altering file locations in a model (e.g. using feature class to feature class tool)?

texts:
I have a backed up file GDB which I have to use because the current one had some broken models in it. I got this backup delivered on my local D:\ drive and have to copy models from this GDB to a current one, which sits on a network location.

Now the problem is that all the links to data in the models have been reset to this local drive, whereas they should point the network location. When I now edit the model and set back the paths to the correct locations (e.g. in the 'feature class to feature class' tool), all my fieldmaps that were adjusted in the backed up models will change (originally deleted fields appear again, adjusted field names get lost). This is a problem because not only do I have a couple of models where this has to be changed, also the feature classes within them have a lot of fields. This means a lot of tedious work that I want to avoid by all means, especially as the correct field mapping is available in my backed up models.

I’m using ArcGIS 9.3, the ‘Store relative path names’ option is checked in all the models. May that have caused the problem? It does however not make a difference if I change to ‘absolute path names’ now, as the field map gets lost as soon as I change the location of my data in the model. This question may be a basic one, but I could not find a solution so far, neither in the ArcGIS help nor on the web. Maybe someone can point me in the right direction?


texts:
I don't understand why if I do "manually" some algorithms I get results much faster than when I insert the same in a pyqgis code (with the same input).
This happens, for example, with the extract nodes algorithm.
I wrote a code in which I call the algorithm as follows:

p=processing.runalg('qgis:extractnodes', polylayer, None)

points = processing.getObject(p['OUTPUT'])

The whole process slows down considerably during the execution of this algorithm (which appears on the top bar, so I am sure that the problem is right on the extract nodes), taking about an hour for provide a result that I would normally be able to achieve in a few seconds.


texts: How can I easily determine the precision of an OGR geometry?

texts:
I'm writing a python tool to update some river catchment boundaries and keep running into geometry errors, such as

WARNING: TopologyException: Input geom 1 is invalid: Self-intersection at or near
point 1590337.0488225699 100863.34768028426 at 1590337.0488225699 100863.34768028426

If I call .Buffer(0) on the geometry, the problem goes away, but then after writing out to shapefile and reading the feature back in, the problem returns.

I think I'm running into a floating point precision error - the coordinate system is in metres, so there is no need to have so many decimal places in the geometry coordinates. I found that if I read each point from the geometry, round to 2dp, then add the point to a new geometry, the problem goes away.

I don't believe there is a method in OGR or shapely to do this rounding (correct me if I'm wrong!), so I'm happy to do it manually. The issue is that not all of our data is in metres - sometimes the inputs are in WGS84, with map units in degrees. Rounding to 2dp is not going to help me here. What is the best way to decide how much to round my coordinates by?

I've tried using a percentage of max(height, width), but it feels a bit clunky. Is it better to just have a lookup table of coordinate systems and round to, say 8dp if WGS84, or 2dp if anything else?


texts: google.maps.ROADMAP doesn't show on OL unless I change base layer and re apply

texts:
I have web app with OL 2.13 and google street as base layer.
Everything worked fine till couple of days ago, suddenly (without any change) the map loads white (no errors in console) and only if I load the map with different base layer (hybrid or satellite) and than choose google street , than the layer is drawn.

Any idea what might cause this behavior ?

 map = new OpenLayers.Map('myMap', {
        units: 'm',
        zoomMethod: null,
        projection: epsg900913,
        displayProjection: epsg4326
    });

    var ggl = new OpenLayers.Layer.Google('1',{type: google.maps.MapTypeId.ROADMAP });
    var sat = new OpenLayers.Layer.Google('2', {type: google.maps.MapTypeId.SATELLITE});
    var hybrid = new OpenLayers.Layer.Google('3', {type: google.maps.MapTypeId.HYBRID});

    map.addLayers([ggl,hybrid,sat]);

I


texts: Displaying nonspatial data via spatial data in Leaflet

texts:
I have two pieces of data; one is nonSpatial Jobs data and one is a spatial grid (polygon that was turned into geoJson). They are being served through separate API's/ajax calls. A primary-foreign key was created to link the two datasets(Cell ID or CID that is created from the southwest coordinate of each grid cell. Ex n89, w113 = CID:n89w113). My goal is for the user to be able to create and display the Jobs data based on the grid cell. Thus fa, I have not been able to achieve this. Assuming that a job already exist with a certain CID (but this job has no spatial value-lat/lng) and there is a corresponding grid cell that has that same CID and is spatial located on a map, how can I use Leaflet (or just javascript) to display the information for the Job corresponding to that grid cell (using a mouseover/click event and popup method like .bindPopup)? Here's my current logic, but I think there is something amiss...

 var globalArrayJobsCID = [];
 $.ajax for Jobs data{
   ...
   data.forEach(function (value) {
     var cid = value.cid;
     globalArrayJobsCID.push(cid);
   ...
   };
   $.getJSON("url', function(data) {
     grid = L.geoJson(data, {...};
     onEachFeature: function(feature, layer) {
     var id = feature.properties.cid;
     globalJobsArrayCID.forEach (item) {
        if(item == id) {
          layer.bindPopup(<Jobs data>);
   });
};


texts: How do I set label to rotate with segment in QGIS?

texts:
Possible Duplicate:
  How to create curved labels in QGIS

In MapInfo Pro I have an option to rotate a label with segment (this is nice for labeling roads for example).

How do I do the same in QGIS ?


texts: Formatting Google Places API GeoJSON and Import to QGIS?

texts:
I'm trying to export JSON or XML data to my desktop and import it to QGIS.

This is the URL I'm using but it appears to be incorrectly formatted:

https://maps.googleapis.com/maps/api/place/nearbysearch/json?location=51.503186,-0.126446&radius=9000&keywords=exchange&types=bank&key=AIzaSyDyGA1g71hnK85zIMZ7CVp0CKoiRfG_Fpk

My goal is to query the Google API and receive a JSON or XML file that I can then load into QGIS/ArcGIS... etc. as a feature dataset. The JSON text that is received with the API query has incorrect syntax and this fails to load, please advise?


texts:
Is it possible to link two data frames so that they mirror each other?  I know I can set the extent of one data frame to that of another data frame, but then you can only pan/zoom in the parent frame.  Basically just want the two data frames to mirror one another.

I would like the flexibility to pan and zoom in which ever data frame is active, not just the "parent" data frame.  This is different from setting the extent of one data frame to match that of another, where only the parent data frame has the ability to pan and zoom.  I am using ArcMap 10.1.

I have made this suggestion to ArcGIS Idea: Mirror Data Frames - ArcGIS Idea


texts: How to get the "Join attributes by location" features on a QGIS Mac version

texts:
I am using QGIS 3.2.0Bonn on a macOS High Sierra (10.15).

I am trying to do a simple procedure on QGIS for Mac, following a tutorial which was built for Windows (so it seems).

What I want to do is to perform spatial joins, following this very awesome tutorial page.

The problem is that the option "Take summary of intersecting features" is not available at the "Vector -> Data Mangement Tools -> Join attributes by location" dialog box on my QGIS version. This is how the option window looks like to me:

I have seen similar question here. But both answers to this question referred to using the feature but did not explain how to "get it" or where to find it on QGIS for Mac.

Is there a solution to this feature on QGIS for Mac?


texts:
I want to fill my polygons in openlayers 3 to make them look like this:

In QGIS I can provide a svg image to create this kind of pattern. How can this be achieved in openlayers 3?

Background / Research so far

I intensively read through the API documentation and found out that the ol.style.Fill class accepts an ol.ColorLike object.
A ol.ColorLike Object again accepts a CanvasRenderingContext2D.fillStyle, which can be an image pattern or a gradient. So I guess it should be technically possible to tweak the openlayers API to achieve a patterned polygon fill.

See these links for further information:

http://openlayers.org/en/latest/apidoc/ol.style.Fill.html
http://openlayers.org/en/latest/apidoc/ol.colorlike.html
https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/fillStyle
https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/createPattern

Putting the Pieces together

This is my code so far and here begins the trouble. I can't find a way to get a working instance of CanvasRenderingContext2D. It always returns with undefined.

var canvas = document.getElementsByClassName('ol-unselectable') // filter <canvas>
var ctx = canvas.getContext("2d");
var img = new Image();
img.src = 'https://mdn.mozillademos.org/files/222/Canvas_createpattern.png';
var colorLike;

img.onload = function() {
      var pattern = CanvasRenderingContext2D.createPattern(img, 'repeat');
      CanvasRenderingContext2D.fillStyle = pattern;
      colorLike = CanvasRenderingContext2D.fillStyle
}

var style = new ol.style.Style({

      fill: new ol.style.Fill({
           color: colorLike // ol.ColorLike object
      })
  })

To see the full code visit: jsfiddle

Is there a way to access the polygon drawing canvas prior initializing it? Or how can I create a correct CanvasRenderingContext2D instance here?


texts: Why "DataBase Connections" mapped to "Dataset DataBase Connections" in ArcCatalog?

texts:
I am trying to Export data from a geodatabase by a existed sde file(created by ArcCatalog),
the Error Messges:

  Executing: ExportCAD 'DataBase Connections\Connection to
  GIS-WANG.sde\SDE.water\SDE.ControlValve' DWG_R2010 D:\117.DWG
  Ignore_Filenames_in_Tables Overwrite_Existing_Files # Start Time: Thu
  Oct 13 16:46:59 2011 ERROR 000622: Failed to execute (ExportCAD).
  Parameters are not valid. ERROR 000732: Input Features: Dataset
  'DataBase Connections\Connection to
  GIS-WANG.sde\SDE.water\SDE.ControlValve' does not exist or is not
  supported Failed to execute (ExportCAD). Failed at Thu Oct 13 16:46:59
  2011 (Elapsed Time: 0.00 seconds)

Why "DataBase Connections" mapped to "Dataset DataBase Connections"?


texts: Creating atlas of different layers on the same place (QGIS)

texts:
I know the atlas function in QGIS can automate creation of maps of the same layer (say vegetation type) of different places (say natural reserves).

Is there a possibility to automate the creation of different maps with different layers (vegetation type, climate, hours of sun) of the same region or place?

So, kind of reversing the atlas function to have it cover the same area with different attributes.

Any suggestions or links to the answer?


texts: ESRI fc is called database.DBO.fcname and version is called SDE.fcname

texts:
ArcSDE 9.3.1 and MS SQL 2008 R2
In ArcCatalog the feature class is called database.DBO.fcname and when I look at the connection properties in ArcCatalog the default is called DBO.Default and the other versions are called SDE.versionname1 and SDE.versionname2.  We just migrated to MS SQL 2008.  I did not do the install of sde on the new server.  The databases were not created new on the new server instead they were backed up and then restored to the new server from a MS SQL 2000 db and then upgraded to 2008 databases.  Is the sde on SDE.versionname1 referring to the schema or the owner?  Thanks.


texts: Does ArcMap have search and replace function over several fields at once for NULL values?

texts:
I am trying to replace all "Null" values to "0", over all fields.
I am quite sure this is wishfull thinking, but it's worth asking ! Is there a tool which performs this ? (as well as the opposite operation) ?


texts: GeoServer and local PostgreSQL database without Internet

texts:
simple question: can I work on GeoServer and local PostgreSQL database on my PC without need for Internet connection ?

would I be able to connect GeoServer to the database and create layers ? also would I be able to use pgAdmin and postGIS full usage ?


texts: Randomly creating a subset from a feature class having a large amount of data in it's attribute table

texts:
I have a feature class which has 135270 entries in its attribute table and I want to randomly select about 25% of this data for better visualization of the feature class on a web application. However, I don't want to delete any entries or create any new entries.
How can I do this on ArcGIS Pro?


texts: Overpass API - Multiple ways for same road

texts:
I am running a query for Ways by name using a regex. I recurse down to get the nodes and all data returned appears fine with the exception that the one "road" with the one name thats being queried returned multiple ways. Ultimately all the ways attach and is physically the same "road". I am using this as a typeahead for a user to select a "road" and then later I will use that "road" they selected to offer them a list of other Ways that intersect with this "road"... As you can probably see when I run the later query for a list of intersecting Ways i cannot just simply reference just one Way ID from the initial query as there are many Ways that represent what a user would consider the "road" they were looking for... Am I missing anything? Is there any sort of "Parent" way that can be referenced. Why is one road represented as more than one Way? Is it simply a data quality issue that someone needs to merge them or is this by design? Is there any way in the API for me to write my followup query that starts with one of the ways at random but then basically say (in pseudocode)

Give me way # 1234, plus any ways that have the same name as 1234 and share at least one node (meaning they are truly one "Road")
->then return me a list of Ways that intersect with those ways.

I can figure out the query to get the intersections, the more important part is trying to treat the initial way as one single road.

Initially I was thinking I would handle the merge of the Ways in my code and sort of cache a "parent" way that all the individual ways would be children of and then my second query would basically list all the individual ways. Seems like its more complicated for me to do manually and i'm thinking there must be a way to handle this natively in the API...


texts:
Does anyone have style sheets for the shapefile extracts of OpenStreetMap? The layers which are downloaded "Lines" "Multilinestrings" "Points" "Multipolygons" all have attributes associated to them and someone must have dedicated some time towards creating very pretty styles, especially when being open source. Older posts relating to this question direct me to sites with .qml style files although they apply to layers which do not correspond to the more modern shapefiles downloaded from OSM.

I ended up just styling it under my own steam, check it out!


texts:
I'm currently looking to contribute to a project which seeks to integrate GeoRSS RDF properties, and I'm struggling to find precisely where there exists an OWL Document for the ontology itself.

It appears as if the link to the mailing list for the project is dead:

http://www.georss.org/implementations.html

Are they still actively supporting RDF properties?


texts: When creating a confusion matrix, can you have more ground-truth points than the recommended 10-times the number of classes you have?

texts:
Using ArcGIS Pro, I classified a field of grain sorghum (supervises, pixel-based support vector machine) using 5 classes: Soil, Shadows, Leaves, Heads, and Ground targets (this was a UAS study). The spatial resolution of the input raster was about 2.1 cm/pixel, which is very high.

To test the accuracy of the image, you make a confusion matrix, which is a random assortment of test points in the pixel using ground-truthed data. The rule of thumb for this procedure is that you don’t want to use more than 10-times the number of test points than you have classes. Since I had 5 classes, each class of test points had 50 points. These points were randomly distributed throughout the image to avoid bias.

The problem that I’m having is that using those 50 points per class, I could not get a kappa value of below 1. Which indicates a very fine accurate classification, but since there is some error, I do want to detect it. To do this, I increased the number of points per class to 300; with this, I was able to compute a kappa value of 0.98, indicating a very high accuracy. These points were also randomly distributed. It should be noted that I placed them myself on the image.

My question is this: Is it ok to use more than the recommended “10x the number of classes” guideline to get test points for a confusion matrix?


texts: Python geopandas dataframe of polygons -- determine nearest neighbor polygon?

texts:
I am trying to figure out how to dynamically create expanded regions of interest based on polygon geometries in geopandas until some threshold is satisfied (essentially custom regions across the contiguous US).

I have a geopandas dataframe with the following columns:

unitspaces_geodf[['unit_space_count', 'city', 'state_code', 'latitude', 'longitude', 'cbsa_code', 'geometry']]

where geometry is the corresponding polygon for the cbsa_code (generated from a shape file).

I can get a total count of unit_space_count by grouping the dataframe on cbsa_code:

unitspaces_geodf.groupby('cbsa_code')['unit_space_count'].sum()

Based on the sum() value of unit_space_count in each cbsa_code (let's say a threshold of 100) I want to determine the next nearest geometry and then combine the two geometries (and concatenate the cbsa_code) until unit_space_count is above the threshold. This is essentially creating a new neighborhood/region. Then remove these two (or more) cbsa_code entries from the pool of available entries to concatenate with.

So in the example above, the last line of the groupby clause shows a  cbsa_code of 12660 and the total unit_space_count is 72.

For this record, I want to determine the nearest neighbor (using the  geometry column and hopefully an out-of-the-box geopandas or shapely method) to generate a new combined cbsa-code (something like 12660-12620 if 12620 happened to be the nearest neighbor) and a new unit_space_count of 1268 (1196 + 72).

I think I may need to first create a map of all the grouped values to see which regions should be joined with which, but after that I need help with determining how to do these calculations.


texts: Attribute extraction using buffer on top of a raster layer

texts:
How can I extract attribute information from a raster map?

I work with camera traps and I am interested in collecting habitat information off a raster sheet. I am interested in a certain radius around the point. In the past, I used a buffer around the camera points and extracted the information, but that was not using a raster layer.


texts: What projection to use to calculate polygon areas of city to global size from lat/lon data?

texts:
I have a set of bounding boxes in WGS:84, and I would like to calculate their areas using Python.

The bounding boxes are of all sizes, from city sized to covering the entire Earth.
The bounding boxes may cross the dateline, but I'd imagine >99% of them don't.
The areas don't need to be exact. To within 100^2 km is fine.

I will be doing the reprojection using pyproj in Python, and the area calculation's probably using Shapely. The question is - what projection should I use?

Wikipedia has an entire set of equal-area projections - https://en.wikipedia.org/wiki/Map_projection#Equal-area

Over on SO, there's a question dealing with this, but the answers all seem to have caveats that make them unsuitable for my purpose:

Which projection do I reproject to before doing the area calculation?

Edit

If I use the maths from here which @barrycarter helpfully provided, I end up with this Python:

import math

# Radius of earth in km^2
R = 6371
lat1 = -90
lat2 = 90
lon1 = -180
lon2 = 180

part1 = 2*math.pi*(R*R)

part2 = (math.sin(lat1)) - (math.sin(lat2))

part3 = (lon1 - lon2) / 360

answer = part1 * part2 * part3
print(answer)

Giving an answer of ~456 million ^2. The problem is, the earth's area is ~510km^2. So the result is over 10% out.


texts: Database connection times - PostGreSQL vs Oracle (ArcSDE)

texts:
I have 2 SDE instances.

Both have the same amount of data (2000 datasets both raster and
vector).
One is PostGreSQL 9.2 with ArcSDE 10.2.1
One is Oracle 11g with ArcSDE 10.2.1

So basically the only difference is the RDBMS.
The oracle instance takes 5 seconds to open in ArcCatalog.
The PostGreSQL instance takes 26 seconds to open in ArcCatalog.

Does anyone know why this is happening and how we can get PostGreSQL instance to open just as fast as the Oracle one.


texts: Cannot georeference an image using a custom projection in QGIS

texts:
I am trying to georeference a map using a custom projection I created in QGIS. I get the error Transform failed: "Failed to compute GCP transform: Transform is not solvable" Does anyone have any idea what is happening? I can create layers using the custom projection and no problem.
Here is the custom CRS:
DERIVEDPROJCRS["NewGrid",BASEPROJCRS["NAD83 / UTM zone 11N",BASEGEOGCRS["NAD83",DATUM["North American Datum 1983",ELLIPSOID["GRS 1980",6378137,298.257222101,LENGTHUNIT["metre",1]]],PRIMEM["Greenwich",0,ANGLEUNIT["degree",0.0174532925199433]],ID["EPSG",4269]],CONVERSION["UTM zone 11N",METHOD["Transverse Mercator",ID["EPSG",9807]],PARAMETER["Latitude of natural origin",0,ANGLEUNIT["degree",0.0174532925199433],ID["EPSG",8801]],PARAMETER["Longitude of natural origin",-117,ANGLEUNIT["degree",0.0174532925199433],ID["EPSG",8802]],PARAMETER["Scale factor at natural origin",0.9996,SCALEUNIT["unity",1],ID["EPSG",8805]],PARAMETER["False easting",500000,LENGTHUNIT["metre",1],ID["EPSG",8806]],PARAMETER["False northing",0,LENGTHUNIT["metre",1],ID["EPSG",8807]]]],DERIVINGCONVERSION["Affine",METHOD["Affine parametric transformation",ID["EPSG",9624]],PARAMETER["A0",-589354.7808210109,LENGTHUNIT["metre",1],ID["EPSG",8623]],PARAMETER["A1",3.2622101349044312,SCALEUNIT["coefficient",1],ID["EPSG",8624]],PARAMETER["A2",-0.09032554258992082,SCALEUNIT["coefficient",1],ID["EPSG",8625]],PARAMETER["B0",-14081478.9932015,LENGTHUNIT["metre",1],ID["EPSG",8639]],PARAMETER["B1",0.09032554258992082,SCALEUNIT["coefficient",1],ID["EPSG",8640]],PARAMETER["B2",3.262210134904431,SCALEUNIT["coefficient",1],ID["EPSG",8641]]],CS[Cartesian,2],AXIS["(E)",east,ORDER[1],LENGTHUNIT["metre",1]],AXIS["(N)",north,ORDER[2],LENGTHUNIT["metre",1]]]


texts: How to position a guide at a specific point in the Print Composer?

texts:
Rather than drag guides onto a print composer, I would like to type in a number to set them at a specific point. Is it possible to do this?

E.g. I want to make sure I snap objects to margin guides at 10mm from the page edges. It's fiddly to use the mouse and I would have to zoom it to see enough markings on the ruler.


texts: PDAL Filter output is same as input file

texts:
I've applied SOR filter using PDAL python.Below is the code snippet of the same,

json =
 """
{
  "pipeline":[
    "D:/Lidar_collect_3/output/output_1.las",
    {
      "type":"filters.outlier",
      "method":"statistical",
      "mean_k":6,
      "multiplier":1.0
    },
    "D:/Lidar_collect_3/output/output.las"
  ]
}
"""

pipeline = pdal.Pipeline(json)
pipeline.validate()
pipeline.execute()

The output.las created has the same number of points as input(looks same as the input). I've tried with different mean_k and multiplier values, but no result.

Where did I go wrong ?


texts: Problem with GeoServer modifying a style when uploading an SLD via the REST API

texts:
I have an SLD called my_data.sld (created in QGIS 3.2.x) with looks like this:

<?xml version="1.0" encoding="UTF-8"?>
<StyledLayerDescriptor xmlns="http://www.opengis.net/sld" xmlns:xlink="http://www.w3.org/1999/xlink" xsi:schemaLocation="http://www.opengis.net/sld http://schemas.opengis.net/sld/1.1.0/StyledLayerDescriptor.xsd" version="1.1.0" xmlns:se="http://www.opengis.net/se" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:ogc="http://www.opengis.net/ogc">
  <NamedLayer>
    <se:Name>my_data</se:Name>
    <UserStyle>
      <se:Name>my_data</se:Name>
      <se:FeatureTypeStyle>
        <se:Rule>
          <se:Name>Single symbol</se:Name>
          <se:PointSymbolizer>
            <se:Graphic>
              <se:Mark>
                <se:WellKnownName>circle</se:WellKnownName>
                <se:Fill>
                  <se:SvgParameter name="fill">#e15989</se:SvgParameter>
                </se:Fill>
                <se:Stroke>
                  <se:SvgParameter name="stroke">#232323</se:SvgParameter>
                  <se:SvgParameter name="stroke-width">0.5</se:SvgParameter>
                </se:Stroke>
              </se:Mark>
              <se:Size>7</se:Size>
            </se:Graphic>
          </se:PointSymbolizer>
        </se:Rule>
      </se:FeatureTypeStyle>
    </UserStyle>
  </NamedLayer>
</StyledLayerDescriptor>

If I upload SLD file via the GeoServer control panel, then apply it to a layer, the layer is correctly styled, no problem.

However, I want to add upload this style to a workspace and apply it via the rest API, which I do via these commands (following the curl examples):

curl -v -u admin:pass -XPOST -H "Content-type: text/xml" -d "<style><name>my_data</name><filename>my_data.sld</filename></style>" https://localhost/geoserver/rest/workspaces/my_workspace/styles
curl -v -u admin:pass -XPUT -H "Content-type: application/vnd.ogc.sld+xml" -d @/home/sam/my_data.sld https://localhost/geoserver/rest/workspaces/my_workspace/styles/my_data

Both commands appear to work giving < HTTP/1.1 200 OK codes. I have the new style in my workspace but there's a problem with the content of the style. Inspecting the new style in the GeoServer Style Editor control panel shows:

<?xml version="1.0" encoding="UTF-8"?>
<sld:StyledLayerDescriptor xmlns="http://www.opengis.net/sld" xmlns:sld="http://www.opengis.net/sld" xmlns:gml="http://www.opengis.net/gml" xmlns:ogc="http://www.opengis.net/ogc" version="1.0.0">
  <sld:NamedLayer>
    <sld:Name>my_data</sld:Name>
    <sld:UserStyle>
      <sld:Name>my_data</sld:Name>
      <sld:FeatureTypeStyle>
        <sld:Name>name</sld:Name>
        <sld:Rule>
          <sld:Name>Single symbol</sld:Name>
          <sld:PointSymbolizer>
            <sld:Graphic>
              <sld:Mark>
                <sld:WellKnownName>circle</sld:WellKnownName>
                <sld:Fill/>
                <sld:Stroke/>
              </sld:Mark>
              <sld:Size>7</sld:Size>
            </sld:Graphic>
          </sld:PointSymbolizer>
        </sld:Rule>
      </sld:FeatureTypeStyle>
    </sld:UserStyle>
  </sld:NamedLayer>
</sld:StyledLayerDescriptor>

Clearly tags with se:SvgParameter have not been translated into whatever format the style is in now.

I've tried to modify the <StyledLayerDescriptor> to match the manual upload that worked, without success.

I thought the issue might be related to the  "Content-type:application/vnd.ogc.sld+xml" but can't find an appropriate content type either.

What should I try next?


texts:
I have a QGIS project where a SHP-layer contains the IDs of plots besides vector data.

I want to create a form with QTDesigner which enables me to enter the contact information of the landowner(s) for each plot in QGIS. So by clicking on the "identify features"-button the form should open and then I should be able to enter the landowner information. The plot-ID should be a value that is determined and can't be changed.

My biggest question is, how I can consider that some plots can have several, up to 20 land owners. So obviously having all this data on one form is not very good. It should be separated and selectable (tabs, or a drop down menu).

My idea how to handle this in such cases:

I enter the data (street, town, ZIP, phone number) of the first landowner then I push "OK"  thus creating a dataset "landowner1". After this I'm still on the same form, but all the fields where I can enter the contact information are empty again and now I can enter the data for "landowner2", and so on. Since the data would be stored in the attribute table I would also have street1, street2,... town1, town2, ... etc. for each landowner.

Later all this data should be accessible via the "identify feature" and I can select in a dropdown-menu or -list between the landowners.

How can I achieve this?

Please note that I'm have almost no idea about Python or programming. I'm using QGIS 2.12.0.


texts: How to show elevation on mouse hover in QGIS?

texts: I've got a DEM layer and would like to have the status panel in the bottom display the elevation in addition to the mouse coordinate. Can that be done? Using QGIS 2.6.1


texts: Find closest location to given point within distance

texts:
I have table location with column geo_data with DDL:

CREATE TABLE location
(
    id INTEGER PRIMARY KEY NOT NULL,
    geo_data GEOGRAPHY(GEOMETRY,4326),
);
CREATE INDEX index_location_on_geo_data ON location USING GIST (geo_data);

And I use this query to find nearest location to given point:

SELECT ST_AsText(location.geo_data), st_distance(ST_GeomFromText('POINT(37.611100 55.756926)', 4326), location.geo_data) as distance
FROM location
WHERE ST_Dwithin(ST_GeomFromText('POINT(37.611100 55.756926)', 4326), location.geo_data, 1200)
ORDER BY distance
LIMIT 1;

And it works great but I confused by two issues about this query:

There is no functions about to just find one closest location to given point and I should use ST_Dwithin, sort by distance and limit by 1;
In order to work around above limitation I should define my point twice (first in select statement in order to sort result set and second in where clause within function ST_Dwithin). And this fact of duplication is also confusing me.

Is there any solutions to eliminate this drawbacks? Or maybe make this solution more faster.


texts:
I am not very good at js and new with leaflet so i my code may be a bit messy but stil...
I have a problem with my legends, i have 2 legends and many overlays and i want some legends to be "linked" with some overlays.
I followed every example i saw but still i have a problem with the name of the layer, it's like my names don't work so controls can't change legends properly

I made a jsfiddle that can explains more obviously my problem. http://jsfiddle.net/qs6wkru4/3/

I want the legend to change when i click on "Cuivre" and not on others...


texts: How to export Bing Maps layers to Pdf with Arcmap - and get appropriate resolution?

texts:
I've got a GP service that creates a new mxd, adds Bing Layers to it, zooms to a particular extent, then exports a pdf.  Sometimes (when the network is slow, I suspect) the resulting pdf has a mixture of tiles from different resolutions.  Is there some way to set a timeout that causes arcmap to wait longer for tiles to be received for the scale being plotted?

Update

On closer examination, the timeout may be a red herring.  I notice that IActiveViewEvents.AfterDraw fires many times as the pdf is being generated.  This suggests that the map is being drawn in chunks.  Looking at the pdf, I see that the low res areas extend all the way across the map, so I guess the chunks are horizontal strips.  Only a few of the strips are lo res.  Assuming the chunks are drawn from top to bottom, it seems like if it were a timeout issue then only the top strip would show low res.  Notice how the low res strips are in the middle though.


texts: Calculating Topographic Ruggedness Index in ArcGIS Desktop?

texts:
Does anyone know how to calculate Topographic Ruggedness Index (a.k.a Terrain R.I.) in ArcGIS Desktop without access to command line ArcInfo Workstation?
"The topographic ruggedness index (TRI) is a measurement developed by Riley, et al. (1999) to express the amount of elevation difference between adjacent cells of a digital elevation grid. The process essentially calculates the difference in elevation values from a center cell and the eight cells immediately surrounding it. Then it squares each of the eight elevation difference values to make them all positive and averages the squares. The topographic ruggedness index is then derived by taking the square root of this average, and corresponds to average elevation change between any point on a grid and it’s surrounding area." -- from an aml arcscript by Jeffrey Evans


texts: QGIS: Can I add a column to an attribute table as a function of two other columns?

texts:
I have a layer of output areas in a city, with two fields for "TotalArea" and "NaturalArea", and I'd like to include a field in the same shapefile that is essentially "NaturalArea/TotalArea". Is there a way to do this?

What if some output areas have null entries for "NaturalArea"?


texts: Why does QGIS do an unintended datum shift to WGS84 in the map canvas

texts:
I'm a new QGIS user running 2.12 Lyon. I've encountered an issue with map canvas units and an unexpected and transparent datum transformation to WGS84. I need help figuring out if I've missed something - Or if the program is or isn't working as designed. To duplicate my issue:

1st test:
- Create a point shapefile with a point at Lon: 12 00 00.000 E Lat: 06 30 00.000S - select CRS GCS Camacupa.

Add it to a new project, which will take CRS GCS Camacupa by default.
Change the map canvas units to DMS, which obtains the original Lon/Lat values for the point.
Change the map CRS to PCS Camacupa / UTM zone 33S, which obtains the correct values for Camacupa / UTM zone 33S: X: 168151.91 mE Y: 9280605.47 mN.
Now change the map canvas units to Degrees, Minutes, Seconds (needs at least two tries, but does work), which obtains values in WGS84: Lon: 06 30 05.370E Lat: 11 59 49.278S. (Externally verified). The GCS default datum transformation parameters are used.

2nd test:
- Reproject the layer itself to Camacupa / UTM zone 33S, add the layer to a new map, and change the map canvas units to DMS, which again obtains values in WGS84.

3rd test:
- Change the shapefile GCS to WGS84 and add it to a Camacupa / UTM zone 33S map. A datum shift is performed and the resulting Camacupa XYs are correct. Change the units to DMS and the readout reverts to WGS84.

These and other tests of this behavior seem to indicate that if the projected map GCS references a local datum such as Camacupa, the Degree or DMS projected map readout will be transparently transformed to WGS84.
My expectation is that the projected map canvas unit Degree or DMS readout would reflect the project CRS GCS.
If the program is only intended to provide the correct Lon/Lat coordinates when the map is de-projected, then it should not allow a Degree or DMS readout to be selected when the map is projected.
Better yet, it should allow a Degree or DMS readout to be selected for a projected map, and should not perform the shift to WGS84.

Is it me or the program? Has QGIS always done this? In any event, the transparent and unintended datum shift in the map readout could cause some serious confusion.


texts: Creating isochrones in ArcGIS for Desktop?

texts:
Is it possible to create isochrones (lines of equal travel time to or from a certain point) in ArcGIS? I have a street network, with the streets having a speed limit attribute, and I need to create a map of travel times to or from a certain point on the network. I know that isochrones in PostGIS and QGIS have been discussed here already, but what about ArcGIS? Also, I would like the final output to be polygons, not lines (i.e., the space between each two isochrones should be a polygon representing all land within a certain travel distance).

I know I can generate a lot of random point features, compute the travel time to each, interpolate that figure between the points, and reclassify the resulting raster into intervals as needed; I've since found that something like this has already been discussed in Using ArcGIS Desktop to create outline (isochrone) around points?, but is there a more elegant way of creating isochrones?


texts: User interface for QGIS processing scripts

texts: Is it possible to add combo-boxes, option groups and similar items to QGIS processing scripts? The documentation mentions text-boxes ('string', 'number'), file browser etc. I would like to add a combo-box with a list of values - should I make my own Qt from?


texts: Installing mapserver in cygwin with regex.c

texts:
This is my first time installing mapserver in cygwin, but I am an experienced user of both cygwin and mapserver.

The thing is that I'm getting a regex issue after doing cmake in the build directory inside the mapserver-6.4.1 directory (after doing tar -zxvf mapserver-6.4.1.tar.gz, etc, etc). My cygwin installation meets all the requirements afaik to build mapserver. I'm not sure, though, if regex.h is causing a problem. This is what I get after running cmake:

--
Gery@gery /opt/mapserver/mapserver-6.4.1/build
$ cmake .. -DWITH_CLIENT_WMS=1 -DWITH_CLIENT_WFS=1 -DWITH_SOS=1 -DWITH_KML=1 -DWITH_PHP=1 -DWITH_PERL=1 -DWITH_PYTHON=1 -DWITH_GD=1 -DWITH_GDAL=1 -DCMAKE_PREFIX_PATH="/opt/gdal/gdal-1.11.0" -DWITH_OGR=1 -DWITH_PROJ=1 -DCMAKE_LEGACY_CYGWIN_WIN32=1 -DWITH_ICONV=0 -DWITH_EXEMPI=0 -DWITH_MYSQL=0
-- Defining WIN32 under Cygwin due to CMAKE_LEGACY_CYGWIN_WIN32
-- /usr/include/php/main
-- Found PHP5-Version 5.5.16 (using /usr/bin/php-config)
-- * Summary of configured options for this build
--  * Mandatory components
--   * png: /usr/lib/libpng.dll.a
--   * jpeg: /usr/lib/libjpeg.dll.a
--   * freetype: /usr/lib/libfreetype.dll.a
--  * Optional components
--   * GDAL: /opt/gdal/gdal-1.11.0/libgdal.a
--   * OGR: /opt/gdal/gdal-1.11.0/libgdal.a
--   * GD: /usr/lib/libgd.dll.a
--   * GIF: /usr/lib/libgif.dll.a
--   * MYSQL: disabled
--   * FRIBIDI: /usr/lib/libfribidi.dll.a
--   * GIF: /usr/lib/libgif.dll.a
--   * CAIRO: /usr/lib/libcairo.dll.a
--   * SVGCAIRO: disabled
--   * RSVG: disabled
--   * CURL: /usr/lib/libcurl.dll.a
--   * PROJ: /usr/lib/libproj.dll.a
--   * LIBXML2: /usr/lib/libxml2.dll.a
--   * POSTGIS: /usr/lib/libpq.a
--   * GEOS: /usr/local/lib/libgeos_c.dll.a
--   * FastCGI: /usr/lib/libfcgi.dll.a
--   * Oracle Spatial: disabled
--   * SDE: disabled
--   * Exempi XMP: disabled
--  * Optional features
--   * WMS SERVER: ENABLED
--   * WFS SERVER: ENABLED
--   * WCS SERVER: ENABLED
--   * SOS SERVER: ENABLED
--   * WMS CLIENT: ENABLED
--   * WFS CLIENT: ENABLED
--   * ICONV: disabled
--   * Thread-safety support: disabled
--   * KML output: ENABLED
--   * Z+M point coordinate support: disabled
--   * XML Mapfile support: disabled
--  * Mapscripts
--   * Python: ENABLED
--   * PHP: ENABLED
--   * PERL: ENABLED
--   * RUBY: disabled
--   * JAVA: disabled
--   * C#: disabled
--   * Apache Module (Experimental): disabled
--
-- Will install files to /usr/local
-- Will install libraries to /usr/local/lib
-- Configuring done
CMake Error at CMakeLists.txt:233 (add_library):
  Cannot find source file:

    //regex.c

  Tried extensions .c .C .c++ .cc .cpp .cxx .m .M .mm .h .hh .h++ .hm .hpp
  .hxx .in .txx

-- Build files have been written to: /opt/mapserver/mapserver-6.4.1/build

Gery@gery /opt/mapserver/mapserver-6.4.1/build
$
--

then it stops. make and make install do nothing, just a "stop" message appears:

--
Gery@gery /opt/mapserver/mapserver-6.4.1/build
$ make
make: *** No targets specified and no makefile found.  Stop.

Gery@gery /opt/mapserver/mapserver-6.4.1/build
$ make install
make: *** No rule to make target 'install'.  Stop.
--

Any ideas?


texts: Easy way to plot separate groups of SpatialPolygons in R

texts:
I have SpatialPolygons grouped by 81 polygons and in each there are some other Polygons I'd like to plot them group by group but have little trouble with it.

> rtu_spl
class       : SpatialPolygons
features    : 81
extent      : 450685, 458760, 358519, 364860  (xmin, xmax, ymin, ymax)
coord. ref. : +proj=tmerc +lat_0=49 +lon_0=-2 +k=0.9996012717 +x_0=400000 +y_0=-100000 +ellps=airy +towgs84=446.448,-125.157,542.06,0.15,0.247,0.842,-20.489 +units=m +no_defs
> plot(rtu_spl)
Error in as.double(y) :
  cannot coerce type 'S4' to vector of type 'double'

I can't plot them all so I'd like to view group by group but how to do it?

What's working is viewing like this, for example:

plot(rtu_spl@polygons[[1]]@Polygons[[42]]@coords)

but this one not:

> plot(rtu_spl@polygons[[1]]@Polygons)
Error in xy.coords(x, y, xlabel, ylabel, log) :
  'x' is a list, but does not have components 'x' and 'y'

How to skip any kind of loop and plot a whole group? More, even if I extract from loop like:

pls = NULL
for (i in 1:81) {
  pls = rbind(pls, rtu_spl@polygons[[1]]@Polygons[i])
}

I still can't plot it:

> plot(pls)
Error in xy.coords(x, y, xlabel, ylabel, log) :
  (list) object cannot be coerced to type 'double'

or

> spols = sp::SpatialPolygons(pls)
Error in sp::SpatialPolygons(pls) :
  no slot of name "Polygons" for this object of class "Polygon"

Please give me a hint how to plot a group separately.


texts:
I'm looking for a way to retrieve an image (a satellite one, preferably) from a rectangular area of a map given a minimum and maximum latitude/longitude.
What tools can I use to achieve this?


texts: Which CRS fits "Lambert Conformal Conic Projection, Standard Parallels 46.40 and 49.20"?

texts:
I am trying to georeference a VFR chart in qgis and I can't figure out which CRS to use.

Map projection - Lambert Conformal Conic Projection, Standard Parallels 46.40 and 49.20.

Any ideas which one on the list will work?


texts: How do I account for changing latitude with a spatial filter?

texts:
I'm working with data in latitude/longitude grid form in a non-GIS specialised package (MATLAB) and wish to apply spatial filters to it.

As this data contains a broad range of latitudes and is centred on the North Pole, I need to account for the spacing between points changing with latitude. For example, if I wanted to apply a simple Gaussian filter of radius X km, I can't just convert that radius to Y cells and go - there has to be some kind of correction as the filter width in terms of cells will change with latitude.

How do I attack this problem? Something to do with weighting by latitude?


texts:
I currently use GRASS' r.mapcalc to find the difference between vector and raster data using a loop and temporary files and layers.

Is it possible to do the core calculation between raster with a vector data more directly either within GRASS, in some external tool, or some python script?

#!/bin/bash
TOPO=mytopo
g.region -p rast=mytopo res=10
for file in INPUTS/* ; do
  imbase=${file#INPUTS/}   # strip off the directory prefix
  v.in.ogr input=$file output=temp_a --overwrite
  v.to.rast in=temp_a out=temp_b use=attr column=elev --overwrite
  r.mapcalc "temp_c" = "(if( "temp_b" <= "$TOPO" ,null(),if( "$TOPO" <0,0, "temp_b" - "$TOPO" )))"
   r.out.gdal input=temp_c -c  format=GTiff type=Float32 output=OUTPUTS/$imbase
end
g.remove temp_a
g.remove temp_b
g.remove temp_c

I like GRASS' the ability to do the mapcalc on resolutions and extents other than my source data. but although this works, the process seems seems awkward and slow for numbers of files in the hundreds. Ideally, I'd like something like the below:

 gdalogr_diff.py mytopo.tif PG:dbname=warmerda -sql "SELECT elev[${timeslice}] from temp_output" -f GTiff out_${timeslice}.tif


texts: IDLE keeps restarting when running the arcpy.Clip_management geoprocess

texts:
I am trying to run an IDW on some precipitation points, but when I try to clip the IDW raster to a polygon boundary, it keeps restarting the IDLE shell. This happens when I run it in the shell, and as a complete script. Here is the code:

import arcpy
from arcpy import env
env.workspace = "C:\\someWorkspace"
env.overwriteOutput = True
arcpy.CheckOutExtension("3d")

#Declare local variable, the points to be interpolated
points = "PrecipKansas2014"

#Making the points to be interpolated a feature layer, for processing in IDLE
arcpy.MakeFeatureLayer_management(points, "points_lyr")

#IDW
arcpy.Idw_3d("points_lyr", "RASTERVALU", "precipNew")

#Clip IDW raster to the polygon state boundary
arcpy.Clip_management("precipNew", "KansasBoundary", "idwClip")

This is as far as I get, as the whole program restarts. The next step would be to arcpy.ExtractByMask() to get data from a specified region, but that will come later.

Using ArcGIS version 10.7.1, no patches applied.


texts: I am in need of the correct syntax for loading WFS layer using OpenLayers. I have gone through many examples on the OpenLayers site and other examples, but can't figure out how to use the necessary and optional options like strategies, protocols etc


texts:
I have 198 tiles of a DEM from which I want to extract contour lines, but doing the operation 198 times is ungainly.

I tried SAGA's Merge raster layers, but it stops into this error:

Oooops! The following output layers could not be open

Merged Grid: C:\Users\USER\AppData\Local\Temp\processing\9833d17c1e3845ddbd7717b1c3084920\MERGED.tif

The above files could not be opened, which probably indicates that they were not correctly produced by the executed algorithm

Checking the log information might help you see why those layers were not created as expected

This algorithm requires SAGA to be run. A test to check if SAGA is correctly installed and configured in your system has been performed, with the following result:

SAGA seems to be correctly installed and configured

The Python error in the message log says:

2016-05-22T17:59:45 1   Traceback (most recent call last):
          File "C:/Users/USER/.qgis2/python/plugins\processing\gui\ProcessingToolbox.py", line 191, in executeAlgorithm
            dlg = ParametersDialog(alg)
          File "C:/Users/USER/.qgis2/python/plugins\processing\gui\ParametersDialog.py", line 42, in __init__
            AlgorithmExecutionDialog.__init__(self, alg, self.scrollArea)
          File "C:/Users/USER/.qgis2/python/plugins\processing\gui\AlgorithmExecutionDialog.py", line 110, in __init__
            isText, help = self.alg.help()
          File "C:/Users/USER/.qgis2/python/plugins\processing\algs\saga\SagaAlgorithm.py", line 510, in help
            name + '.rst'))
          File "C:/Users/USER/.qgis2/python/plugins\processing\gui\Help2Html.py", line 55, in getHtmlFromRstFile
            print s
        IOError: [Errno 9] Bad file descriptor

Similarly, trying GDAL > Miscellaneous > Merge also results in a Python crash, with no log.

An older question seemed to have a similar error, but was fixed by manually downloading the most recent SAGA. I did this, and the error did not change.


texts:
I am a beginner with QGIS.  What I need to do is take a group of zipcodes and group them together (create a territory) in a way that is recorded in an underlying database.

Ideally, I would like to highlight a group of zipcodes and assign a value to them as an attribute (column) in the underlying layer file (database).

Anyone know if that can be done in the mapping software?


texts: How to apply Mapnik Zoom Level Styling via Leaflet Zoom Levels

texts:
I've setup a node mapnik server to render some tiles for polygons. The application I've built to call out to these tiles is in Leaflet

An example of a current mapnik styling rule is below

<Style name="pubLands">
        <Rule>
          <Filter>[simple] = 'blm'</Filter>
          <PolygonSymbolizer fill="#e3cc00"/>
          <LineSymbolizer stroke="black" stroke-width=".1"/>
          <TextSymbolizer size="5" fill="black" face-name="Helvetica Black Regular" halo-fill="#DFDBE3" halo-radius="1" wrap-width="20">[detail]</TextSymbolizer>
       </Rule>
</Style>

Features within this rule are being styled at all zoom levels etc. I would like to only show labels at my map's zoom levels of 13+. How can I modify the style.xml to only label above a certain zoom level, in this case a Leaflet zoom of 13+?


texts: cannot get layers to display in webapp on localhost - geoserver in jetty, app in tomcat

texts:
I’m in the middle of a prototype migration/deployment and have really hit a wall serving up my layers from geoserver.  I’ve geoserver running from the “stand-alone” version running in jetty on one port and the webapp running in tomcat on another port.  The webapp requests data from geoserver via localhost.  This setup works fine on my laptop where I initially developed the prototype.  Since moving everything to a server on the intranet, the webapp can request layers from geoserver, geoserver handles the request, and the webapp never gets anything returned.  What’s even stranger, is if the prototype’s code is run a other hosts and requests data from the aforementioned geoserver, it gets data just fine.  The webapp can successfully access remote WMS layers directly (not from, or cascaded by, my geoserver).

The laptop is running geoserver 2.3.0 and tomcat 7, both from an openSuSE 13.2 rpms, and Oracle's java 1.7.0_79.
The server is running geoserver 2.7.2 (downloaded), and tomcat 7 and OpenJDK 1.7.0_85 from CentOS 7 rpms.


texts: Updating field in geodatabase table depending on other field using ArcPy?

texts:
I have a table in a file geodatabase that has "FieldA" and "FieldB".

I want to update FieldB with one of two values, depending on if there are one or more records with the same value of FieldA.

Example:

FieldA   FieldB

   1        0

   2        1

   2        1

   3        0

I've tried this way

with arcpy.da.UpdateCursor(featureClass, ("FieldA", "FieldB")) as cursor:

for rupd in cursor:

    rows = [row for row in arcpy.SearchCursor(featureClass, 'FieldA=' + str(rupd[0]) )]

    if len(rows)>1:
        rupd[1]=0
    else:
        rupd[1]=1

    cursor.updateRow(rupd)

The table has around 100k records.
It takes around 1 second each record.

Can this performance be improved?


texts: I am using QGIS 2.18.14. I want to create line through contour lines with fixed segments, automatically. I already tried manually with  'Advanced Digitizing Tools'. It works fine but too slow. The goal is, if I enter the length of the segment  e.g. 100m, automatically connect contour lines from a given point to a point target, Or from the selected contour line to the other selected contour line. I think this is possible with some python script but I am beginner in python scripting. I would be pleased with the answer that this could be done, so I would somehow, step by step, solve it. Equidistance of contour lines is 10 m.


texts: Convert shapefile to geographic coordinates with og2ogr

texts:
I'm trying to start plotting maps in python with matplotlib's basemap, but every shapefile I've tried to far seems to have coordinates in metres instead of lat/lon, so I get the following error from readshapefile:

ValueError: shapefile must have lat/lon vertices  - it looks like this one has vertices in map projection coordinates.

Here's output from fiona about the shapefile I'm using:

shape = fiona.open('./data/ESRI/London_Ward.shp')
bounds = shape.bounds
print(shape.crs)

: {'proj': 'tmerc', 'lat_0': 49, 'lon_0': -2, 'k': 0.999601272, 'x_0': 400000, 'y_0': -100000, 'datum': 'OSGB36', 'units': 'm', 'no_defs': True}

print(bounds)
: (503568.2, 155850.8, 561957.5, 200933.9)

ogr2ogr is the only conversion tool I've managed to install so far, is it possible to use it to make the necessary conversion?


texts:
I am lookinig for a way to use an AOI to search and extract data from the data drive on the network at work. So, for example, I have folders of elevation data. Instead of sorthing through each folder and subfolder, I can just use an AOI and it will only give me back the data I need. The Extract Data tool in in the Server Tools toolbox is kind of what I am looking for, but it only performs the extraction on data within the table of contents.

Any thoughts?


texts: Postgis: ST_Buffer breaks because of no forward edges

texts:
I try to buffer a huge road network using ST_Buffer. After 8h of processing I get an error message:

ERROR: GEOSBuffer: TopologyException: No forward edges found in buffer subgraph

Here is my query (adapted from: memory issue when trying to buffer/union large dataset using postgis):

CREATE TABLE Nebenstrassen050 ("geom" geometry(multipolygon,3857), gid serial primary key);
CREATE SEQUENCE bseq;

WITH ordered AS (
  SELECT wkb_geometry AS geom
  FROM Nebenstrassen
  ORDER BY ST_GeoHash(st_transform(wkb_geometry,4326))
),
grouped AS (
  SELECT nextval('bseq') / 100000 AS id, ST_Buffer(ST_Collect(ST_MakeValid(geom)),50) AS geom
  FROM ordered
  GROUP BY id
),
groupedfinal AS (
  SELECT (ST_Dump(ST_Union(geom))).geom AS geom
  FROM grouped
)
INSERT INTO Nebenstrassen050 SELECT * FROM groupedfinal;

I tried to implement ST_MakeValid to avoid this error but it doesn’t show any effect. I’ working on a Win7 64bit machine with Postgres 9.3 and PostGIS 2.1. Any Ideas?


texts: Enabling/Installing/Downloading Portal for ArcGIS?

texts:
How can I install Portal for ArcGIS?  I have installed ArcGIS for server 10.1 on linux.

I read in ArcNews that Portal for ArcGIS is available with the ArcGIS 10.1 release.

How can I enable it?


texts:
i am working on some camera data. I have some points which consist of azimuth, angle, distance, and of course coordinate field attributes. In arcmap I want to draw shapes like this:

The shape is pink.  Can I get the shape with postgres-postgis?

Thanks.


texts: How can I do this geometric-operation in QGIS?

texts:
My problem:

I have 3 polygons (a, b, c) on layer 1 and two other polygons (1 and 2) on layer 2. Now I want to "crop and melt" (forgive me I don't know the terminus technicus) my three polygons (a,b,c) with the polygons (1 and 2) that (on a new layer) I have two new areas: area I (marked in red in my picture) and area II (marked in blue in my picture). Each of my new areas has two parts.

Thank you very much!


texts:
I have a local tile source of OSM tiles.  I'd like to show the tile zoom, x, y on the tile so that I can optimize and create small offline groups of tile for specific areas(polygons).

I can get the tile boundary to show by setting a negative gutter, but I need the tile url info (zoom, x, y) to help with the manual optimization.

I saw an online resource a while back that showed this exact information on a map, but I've lost it :(

I know this is probably a simple problem to solve, but I haven't found any solutions after a while of playing around with it and many searches.     Here is my layer

var newLayer = new OpenLayers.Layer.OSM("GC-h", "tiles/GC/composite_h/${z}/${x}/${y}.png", {numZoomLevels: 19, gutter: -1, isBaseLayer: false});
map.addLayer(newLayer);

TIA!


texts: Merge attributes of selected features not working in QGIS 3

texts:
The following option in the advanced digitizing toolbar: Merge attributes with following features is not working.
According to the following query:
Copy attributes from one feature to empty row of another feature in QGIS 3
I tried to follow this way, but it simply doesn't work in my case.

I am getting nothing in my column after confirming (clicking "Take attributes from selected feature") and clicking OK.

I want the bounded columns in another data attribute table.
How can I use this tool properly?
Is it driven my the following bug described here?
https://issues.qgis.org/issues/11409
https://issues.qgis.org/issues/11405


texts: QGIS - How to fill small gaps in line (other than the Vertex tool)

texts: I suspect this is not as easy as it looks. On the pictured line (of which I have many others), is there a plug in or technique that creates a single line? or am I looking at an epic snap to vertex session?


texts: Adding field to middle of attribute table using ArcPy?

texts:
When executing the add field command in arcpy it always appends the field at the end of an attribute table.

Can someone help me write a code where a field can be inserted in the middle of an attribute table by parsing the data in the fields that would come after the new row to a dictionary, then deleting those rows, adding the new field and then recreating the old fields that were deleted and parsing the data back into the fields?

I know it seems like a lot of extra work but there are times when this would be helpful.


texts: Is it possible to change the geometry without startEditing the layer

texts:
I am working in c++/QT 4.5 with the QGis 2.8.2 API.
I had to change the geometry of features in a layer each second.
Each second new data comes from the Ethernet connection, the application gets the data and calls a function with parameters.

It looks like a real time tracker.
It works only if I put lLayer->startEditing and lLayer->commitChanges but it was too slow.

Here is my code (just an extract. Complete code is too long for the post.)

QgsVectorLayer * lLayer = mMapLayer.value(TRACKS);
lLayer->startEditing();
QgsVectorDataProvider * lDataProvider;
lDataProvider = lLayer->dataProvider();

//calc new random X and Y
PosX =(qrand()%(Xmax-Xmin)+Xmin);
PosY =(qrand()%(Ymin-Ymax)+Ymax);
//create point
QgsGeometry *MyPoint;
MyPoint=QgsGeometry::fromPoint(QgsPoint(PosX,PosY));
QgsGeometryMap MyGeometryMap;
//get the feature of the specify Id
QgsFeatureIterator MyFeatIter;
MyFeatIter = lDataProvider->getFeatures();
QgsFeature MyFeature;
QgsFeatureId MyFeatureId;
while ( MyFeatIter.nextFeature(MyFeature)) {
    if (pTrackId == MyFeature.attribute("TrackId")) {
        MyFeatureId=MyFeature.id();
        MyFeature.setGeometry(*MyPoint);
        MyFeature.setAttribute(Longitude,PosY);
        MyFeature.setAttribute(Latitude,PosX);
    }
}

MyGeometryMap.insert(MyFeatureId,*MyPoint);
bool lResult;
lResult=lDataProvider->changeGeometryValues(MyGeometryMap);
lLayer->commitChanges();

With the startEditing and commitChanges it works, but very slow.
Without the startEditing and commitChanges, the coordinate seems to be modified, but on the layer the feature doesn't move.


texts: Showing relationship between two raster layer

texts:
I have two separate raster layers, one containing sediment transport rate and another raster containing stream length. Now, I want to show the relationship between sediment transport change in different stream length. How should I proceed?

I tried using the profile tool in ArcGIS but that gives me only one raster value against the profile distance. But I want Sediment transport rate against stream distance.


texts: Dissolve on attribute field and location?

texts:
I've got a county parcel shapefile and I'm wanting to find all the properties over 300 acres. When I dissolve based on ownership and search for dissolved properties that sum over 300 acres, some of the "properties" are not actually connected. For example, someone may own 100 acres on one side of the county and 200 acres on the other side of the county. This dissolves to one shape that is 300 acres, but it is obviously not a single 300 acre property. Is it possible to dissolve based on an attribute field AND only parcels that are near each other?

I'm working in ArcMap 10.5 with an Adv license.


texts:
I just created a layer in which I hand drew a lot of polygons.

Now I want to fill out the Attribute table through commands since it will save me a bunch of time.

Therefore, I calculated the area of each polygon using $area/10000 to have the size in ha.

I want to prioritize each area

above 10 ha as Prio 1
each below 1 ha as Prio 3
each in between as Prio 2

Does anyone have a smart solution to the problem?

My closest approach is: IF ("Size ha" > 10, 1, 2)

That however still leaves me with having to distinguish the areas of Prio 2 to Prio 3 manually.


texts: Select By Attribute using geoprocessing without using layers?

texts:
I am selecting features based on attributes within an ArcGIS Add-In. The selections are pretty simple(e.g. "DESCRIPTION = left"). Is there a tool or method of doing this that doesn't require passing layers around? Is there a simple ArcObjects method I may have looked over?

After the selection I will need to pass the selected features into another geoprocessing step - so I need to get the output selection as a path (string).

Currently I am:

1) Creating a feature layer from a given file.

2) Selecting features from the layer.

3) Saving the layer using Copy Features to get the output as a new shapefile.


texts: Tutorial for Kinect 3D scanning over a wide area & export to LAS?

texts: I am interested in using a Kinect to 3D scan a large (~1 acre/0.4 hectare) area, but I am uncertain as to how I could best execute a surface scan of topography. Tutorials that I have seen online show the ability to scan individual rotating objects such as humans rotating on a stool/chair (see Instructable here). What would be the necessary steps/software when the surface remains still, but the Kinect moves? Would I simply set up the Kinect to record the 3D field as I walk around the site?


texts: Isolating a street segment and assigning it a code

texts:
How should I go about making a map of alternate side of the street parking rules (in nyc?)? Does such a one already exist (I can't seem to find one)?

If anyone is familiar with the transportation rules in NYC, certain days of the week you cannot park on a specific side of the road because that side of the road is being cleaned. The location and time varies. But I am interested in overlaying a map of my home borough (Brooklyn) with specific street signs, and then coding them so that I can easily see "this is all the monday sides", "this is all the tuesday sides", "if I am looking for a parking spot on Wednesday I should look here and not there" etc.

To do this, I downloaded a couple of files from NYC Open Data https://data.cityofnewyork.us/ . The two primary data files I have are:

Parking Regulation Sign Locations - it stores information related to:
BoroughCode, StatusOrderNumber, SignSequence, Distance, ArrowPoints, SignDescription

And Parking Regulation Street Segements - BoroughCode, StatusOrderNumber, MainStreet    FromStreet, ToStreet, SideOfStreet.

Obviously the two tables can be joined on the basis of StatusOrderNumber. But looking at the Lion Shapefile put out by the NYC Department of City Planning, they do not keep their roads by road segments; they simply label the entire road.

My more specific question would then be:

How would I isolate a specific road segment (IE: Flatbush between 5th avenue and 8th avenue) from a road (ie: flatbush avenue) and populate it with a specific code that says 'on wednesday, there is no parking on the east side of this road segement between 11am and 1230pm?


texts:
Simply attempting to toggle layers using cartdb and jquery much like this tutorial.
After sniping the console I get init() is not defined?
However this only occurs after adding the 4th button (#large)?
Works fine with 3 (#all,#69,#115)?

  <link rel="stylesheet" href="http://libs.cartocdn.com/cartodb.js/v3/3.11/themes/css/cartodb.css" />

    ALL
    69
    115

    230


texts: Display GeoJSON layer on top a SVG image instead of a map

texts:
I'm very new to GIS, so hope this is the correct place to ask. Not sure if this will even be possible.

This is what I want to achieve:

In short, I want to display a set of polygons, lines etc. in a browser, and then display an overlay which marks specific polygons and lines etc.

This is the way I think it should be approached:

Take a SVG which represents a set of lines and polygons.
Display this SVG using something like Leaflet in a browser, but without displaying a world map which seems to be the basis of Leaflet, OpenLayers etc.
Overlay a GeoJSON layer on top of the SVG.
If possible, I want the coordinates in the GeoJSON file to be relative to a reference point in the SVG.

Is this possible at all?

Also, is the last point possible, that is: specifying what the coordinates in the GeoJSON file should be relative to, or are they always interpreted as GIS coordinates?


texts: How to find self-intersecting polylines using ArcObjects?

texts:
If I have a polyline, how do I figure out whether it is self-intersecting? I tried to use ITopologicalOperator.IsSimple Property, but it always returns true.

Are there any ways of doing these kind of topological checks over individual geometries?


texts: Which is more efficient process in ModelBuilder - Merge/Dissolve or Union/Dissolve?

texts:
I'm creating a model which combines four very large files and dissolves them.  At the moment, my workflow uses the Merge tool and then the Dissolve tool.  However, I was wondering if using the Union tool and then dissolving would be more or less efficient.  I don't need to maintain attributes for my purposes.  I just need to create a layer which contains the geometry.  The feature classes may overlap each other, and they may also contain overlaps within themselves.  As the end result is the same, does anyone know which process would be more time efficient?

Below are screenshots of my workflows:

Merge then Dissolve:

Union then Dissolve:


texts: Making Story Map with two photos that can swipe?

texts:
I am trying to make a story map with some heritage data. I want to have a picture of each heritage site two times(Swipable: that i can swipe between the two photos), one photo for the current and one for earlier years. It can be a swipe or any other tool that is available as long as it is not the same heritage sites for two points.

I am open to suggestions on the platform but i am familiar with ArcGIS Online.


texts:
How can I add a label to the entity (ex. Polygon) at the specify location:

This is how I tried to do it: (entity.polygon = true)

static addLabel(entity) {
        entity.myLabel = new Cesium.LabelGraphics({
            position : Cesium.Cartesian3.fromDegrees(-75.1641667, 39.9522222),
            label : {
                text : 'Philadelphia',
                font : '24px Helvetica',
                fillColor : Cesium.Color.SKYBLUE,
                outlineColor : Cesium.Color.BLACK,
                outlineWidth : 2,
            }
        })
    }

There is no error, but it doesn't show up on the map.


texts: How to reclassify multiple ring buffer using ArcGIS ModelBuilder?

texts:
I want to automate some simple procedure in ArcGIS 10.1:

create a multi-ring buffer around a point at distances 500, 1500, 2500, 3000, 10000 m.
convert to raster
reclassify the multiple ring raster in 1,2,3,4, and 5.

My problem is that in the ModelBuilder when I get asked to enter the Reclass field, which I defined as "distances" it does not appear. Only a value field appears showing 10000.

What is wrong?


texts: OpenGeo Suite - Possible to create input form

texts:
Is it possible to create a user input form such as a simple HTML form to take user input?

The aim of this is to add the user input to the geom data in the DB.


texts: Adding images in Text Annotations using QGIS?

texts:
I would like to add an image in a zone, on the map, to show that an event ocurred.
I don't mind if it is in an Annotation Text or any other functionality.

Is it possible somehow in QGIS?


texts: Excess decimal points showing on QGIS layout grid

texts:
I am using QGIS 3.8.1.

The intervals of my grid are 1.2cm and the labels are set at a 0.6cm offset so they are placed in the middle. I used the draw coordinates custom option to enter my own coordinates rather than from a coordinate reference system. The code I used is as follows and the problem I am encountering can be seen in the image below.

CASE
WHEN @grid_axis = 'y'
THEN substr('ONMLKJIHGFEDCBA', (@grid_number + 0.6 ) / 1.2 , 1)
WHEN @grid_axis = 'x'
THEN (@grid_number + 0.6) / 1.2
END


texts: How to insert raster and other columns using raster2pgsql?

texts:
I would like to have a table with a few more columns than just the raster data. Let's say I'd like to have anotherColumn.

I tried

raster2pgsql -s 3857 -R -a -k -f public.table.image -q -e -F -X public.table myimage.jpg

but I don't think I know how to use the -X option.


texts: Can OpenLayers.Layer.OSM (the OSM tile servers) be used in production environment?

texts:
OpenLayers has an OpenStreetMap layer built in:
OpenLayers.Layer.OSM (are the tiles they use from OpenStreetMap servers or somewhere else?)

Can it be used in a production environment in terms of:

suitability (speed, uptime etc.)
licensing   (ability to use it in a paid mapping system)


texts: Raster file not overlaying to vector layer

texts:
I'm pretty new to GIS and following a tutorial using shape files from Ithaca, NY. I've been able load a number of vector files easily enough but when I add in the .dem raster file it keeps being placed a good distance to the north. I think this issue might be related to a mismatch in Coordinate Reference Systems.

My raster comes from here - https://cugir.library.cornell.edu/catalog/cugir-008186

and I'm using parcel shapefile  from -https://cugir.library.cornell.edu/catalog/cugir-007938

Theoretically the raster should overlay onto the eastern portion of the parcels.

I'm using QGIS Coruna and Postgres10 w/ pgadmin4.


texts: Refine Raster Layer / remove Color bleeding

texts:
I have a Raster layer of Population density in a low resolution.

These raster layer has color bleeding between the different population areas. Is there a way, to remove them in QGIS like color quantisation of the most dominant values to have indexed colors without the bleeding?

And is there a way in QGIS, to "simplify" the areas to get a result like in that picture, maybe something like vectorization and simplify:


texts: Obtaining up-to-date list of US ZIP Codes with Latitude and Longitude Geocodes?

texts:
NOTE: This began as a question on Stack Overflow, which has subsequently been closed.  I also noticed a similar question about Most Up-To-Date Source for US Zip Code Boundaries, but I believe this question is different in that I'm not looking for boundaries as much as I'm looking for coordinates. Sorry for new newbie question.  I'm not sure where to look to find reliable and up-to-date data.

We have a table in our database that has latitude and longitude geocode coordinates paired with US zip codes.  A sample of the data looks like this:

Zip   State  Latitude    Longitude
30000   GA  33.906553   -84.206311
30001   GA  33.810659   -84.607964
30002   GA  33.77429    -84.260712
30003   GA  33.906553   -84.206311
30004   GA  34.113832   -84.294578
30005   GA  34.079927   -84.221166
30006   GA  33.906553   -84.206311
30007   GA  33.968777   -84.43282
30008   GA  33.902022   -84.580318
30009   GA  33.906553   -84.206311

The problem is that our data hasn't been updated for a few years.

Where can I obtain (for free or for purchase) updated data for this table?


texts:
Why, when I use the cost allocation function of Spatial Analyst, is space not allocated in all input source locations (as shown in image below)? In particular, the input raster has 18 spots while the cost function allocates only 14 spaces.  Can I force the function to allocate space in all input source locations? and how?

Full-sized image here: http://i.stack.imgur.com/5k1Od.jpg


texts: Strange shapes and lines while importing shapefile

texts:
I am trying to add a Shapefile over the top of my map of Australia showing the extent of native grasslands.
However every time I add it all these extra lines and shapes appear over the top of the desired output (the grey irregular shapes within the map boundaries).
How do I get rid of these glitchy shapes over the top of everything?


texts: Splitting Polygon by Linestring in GeoDjango?

texts:
In am a Django developer with limited GIS knowledge. In Django I have a polygon and a linestring as follows:

I would like to split the polygon by the linestring to obtain the 4 resulting polygons (or one new multipolygon):

Based on the API docs I thought I might be able to use the union method to get this, but this fails on geometry checking.

Does anyone perhaps have a suggestion on how best to achieve this?


texts: Making simple line more complex using QGIS?

texts:
I am trying to make my own version of code to generate elevation profile for a line drawn over a DEM and I got stuck very early on.

As a simple use case: I have a line that consists of just two points that are, say, 5 km apart. Since my DEM has a resolution of, say, 90 meters, I'd like my sampling points to be 90 meters apart, along the line.

I understand that there are tools in QGIS and GRASS that can achieve this easily (Calculating elevation profile along line from a DEM?) but they just give out the distance of each point along one axis in the final graph.

Ideally, I need to identify all the pixels on the DEM that this line passes over. If this is not possible, at least getting the location of all sampling points along the shapefile would be what I am aiming for - a kind of 3D shapefile with the elevation value for each point along with (lon,lat).

At the very least, it would be great to have an algorithm/pseudo code to make a simple line more complex by adding points to it every x distance from its origin.


texts: From featureclass (or shp) to WKT e GeoJSON

texts:
I use ArcGIS 10.1 without Data Interoperability extension and I want to convert some feature classes (point, lines and polygons) contained in an .mdb. I read some posts but can't convert my file.

This is the code I have (that does not work):

import arcpy
cur=arcpy.da.SearchCursor("CESTINI",["SHAPE@WKT"])
for row in cur:
    x,y = row[0]
    print ("{0},{1}".format(x,y))

Some one can help me?

I saw this link:

Converting geometry to WKT using ArcPy?

http://resources.arcgis.com/en/help/main/10.1/index.html#//002z0000001t000000

I try with this but the result is:

import arcpy
infc = arcpy.GetParameterAsText(0)
for row in arcpy.da.SearchCursor(infc, ["OID@", "SHAPE@WKT"]):
    print("feature {0}:".format(row[0]))
    partnum = 0
    for part in row[1]:
        print("Part {0}:".format(partnum))
        for pnt in part:
            if pnt:
                print("{0}, {1}".format(pnt.x, pnt.y))
            else
                print("Interior Ring:")
                partnum+=1

  Parsing error SyntaxError: invalid syntax (line 9)

I tried with what you suggested but the result is:

      import arcpy

      shp = r"C:\Lavoro\prova_arcpy\punt.shp"
      with arcpy.da.SearchCursor(shp,['SHAPE@WKT']) as cur:
      for row in cur:
      print row[0]

      Runtime error
      Traceback (most recent call last):
      File "", line 2, in
      RuntimeError: unknown geometry token 'SHAPE@WKT'
      What do you recommend?

Someone can explain me the real difference between JSON and GeoJSON?

I was able to use this script to save in a .txt geometry but my problem is that I save only the geometry in 2D and I do not export attributes related to geometry.

import arcpy

shp = r"C:\Lavoro\prova_arcpy\lin.shp"
f= open ("C:/Lavoro/prova_arcpy/conv.wkt","w")
with arcpy.da.SearchCursor(shp,['SHAPE@WKT']) as cur:
for row in cur:
        f.write("wkt_geom "+row[0])

f.close()

How can I do?


texts: Permissive Open source planarize algorithm?

texts:
Is there a permissive open source implementation out there for a "planarize" algorithm (in the style of arcgis planarize - including user modifiable cluster tolerance)?

NB this is not a duplicate of Is there an open source tool to planarize graphs? as alas I need a permissive license, LGPL or BSD, which GRASS doesn't have :(


texts: Problem with the QgsFieldExpressionWidget

texts:
I try to customize the QgsFieldExpressionWidget.
But if I open the Expression Dialog,  the "Fields and Values" are empty.
What I am missing?

lay= iface.activeLayer()
wid = QgsFieldExpressionWidget()
wid.setLayer=lay
scope= QgsExpressionContextUtils.layerScope(lay)# QgsExpressionContextScope()
scope.setFields (lay.fields())
wid.appendScope(scope)
wid.registerExpressionContextGenerator (lay)#QgsProject().instance())
wid.expressionDialogTitle="Test"
wid.setExpression('Foto IS NULL')
wid.show()
print (wid.currentText())


texts: clipping two SpatialPolygons : Error in RGEOSBinTopoFunc

texts:
I want to clip two SpatialPolygons on R without success, I followed the article in the disscution How to perform a true GIS clip of polygons layer using a polygon layer in R?

Polygone 01 :

> polygone1
class       : SpatialPolygons
features    : 1
extent      : -8.673868, 11.98891, 19.43771, 37.09514  (xmin, xmax, ymin, ymax)
coord. ref. : +init=epsg:4326 +proj=longlat +datum=WGS84 +no_defs +ellps=WGS84 +towgs84=0,0,0

Polygone 02 :

> Polygone2
class       : SpatialPolygons
features    : 4
extent      : 0.665381, 12.35598, 30.72105, 37.50386  (xmin, xmax, ymin, ymax)
coord. ref. : +init=epsg:4326 +proj=longlat +datum=WGS84 +no_defs +ellps=WGS84 +towgs84=0,0,0

Code :

clip2 <- gIntersection(Polygone1, Polygone2, byid=TRUE)

Erreur :

Error in RGEOSBinTopoFunc(spgeom1, spgeom2, byid, id, drop_not_poly, "rgeos_intersection") :
  TopologyException: Input geom 0 is invalid: Self-intersection at or near point 8.1451386683704339 37.192197131616837 at 8.1451386683704339 37.192197131616837

Does anyone can help me?


texts: GeoServer caching request not aligned to grid(s) using different EPSG

texts:
First up I've found several other posts on the same topic but neither seem to resolve my problem.

I am trying to create a geowebcache using the embedded geowebcache in Geoserver version 2.11.2

I have been working with two layers both have same problem.  I've set the layers up in Geoserver using the extents computed from the SRS bounds.  I have set up gridsets and seeded the tilecache.  I can see this has been successful from the Tilecache preview in Geoserver.

If I then call the WMS from QGIS then the tile cache is not used (and is very slow as a result).

If I use curl to test the request using a URL I pulled from the layer preview in Geoserver I get the following result of misaglined grids:

geowebcache-cache-result:MISS
geowebcache-miss-reason: request not aligned to grid(s) 'EPSG:27700'

The first layer I've worked with uses EPSG:27700

Gridset config is as follows:

The curl request uses:

C:>"C:\Program Files\cURL\bin\curl" "http://host/geoserver/ws/wms?service=WMS&version=1.1.0&request=GetMap&layers=ws:Aerial%20Imagery%202016&styles=&bbox=383000.0,380999.999998459,400999.999998448,395999.999999761&width=768&height=640&srs=EPSG:27700&TILED=true&FORMAT=image%2Fjpeg" -w content_type -v >nul

The second layer is actually one of the sample layers and sample gridsets that come as part of the Geoserver.  I've used this as test to exclude any variables I may have introduced.  However I get the same result.

Layer users EPSG:4326

The Gridset is:

The curl request is:
C:>"C:\Program Files\cURL\bin\curl" "http://host/geoserver/nurc/wms?service=WMS&version=1.1.0&request=GetMap&layers=nurc:Img_Sample&styles=&bbox=-130.85168,20.7052,-62.0054,54.1141&width=768&height=372&srs=EPSG:4326&TILED=true&FORMAT=image%2Fjpeg" -w content_type -v>nul