I'm trying to extract climate variables in QGIS 3.10.2 for sample points with a raster dataset. The raster comes from ClimateNA () and is available as in ASCII grid (.asc) and NetCDF (.nc) formats.  The raster uses the Projection: Lambert Conformal Conic and Datum: D WGS 1984. The best matching CRS seems to be North_America_Lambert_Conformal_Conic, EPSG:102009  I've set the project CRS to this and verified it for all layers. The raster loads with the CRS undefined and must be set manually, and the sample points, which are actually located in California, are displayed at (0,0). The Google base map appears to be correct.    Does anyone know how I can resolve this?   Another user was able to load it correctly, so hopefully its just a simple step I'm doing incorrectly.
94145
I am a history teacher and I like to make my own maps (I can never find exactly what I want).  I am using QGIS 1.8 and .  I want to reproject their cross-blended hypso rasters into projections that are more familiar looking to my students, like Lambert Conic Conformal.  I have tried changing the crs for the whole project, and the warp and assign functions from the raster menu, and changing the crs for the raster layer itself.  None of these seem to work properly - the resulting maps are unrecognizable and extremely large (file size).  I feel like I am making some kind of basic mistake but I don't know where to begin with this.  Any help would be appreciated.
43376
I'm trying to white a Python plugin in QGIS (2.2) to get, for each pixel of a raster image, its X Y coordinates, as well as, its RGB (3 bands) values.  At first I opened the raster file using: rlayer = QgsRasterLayer(rfileName, rbaseName)  Now I don't know how to get, for example, for pixel (1,1) its coordinates (X,Y) and its RGB color values.  Anybody could help me?  I know that I'll need to implement a DO WHILE, but I don't know the commands to extract this information of each pixel.  Thanks in advance, Mateus
106025
The problem   I have tens of thousands of small polygons for which I want to create buffer/doughnuts for, but I don’t get the units right. I want meters and not degrees, and changing to (what I think is) the right CRS my layer doesn’t longer show. The polygons are small farming plots. I work in QGIS 3.4.15.   Let me take you through it  I start by adding a vector layer. I opt for ‘Directory’ as a source type (Encoding: UTF-8 by default) and under Source (Type: UK. NTF2 by default) I point to the folder in which I store the shapefile.   The default CRS is set to EPSG:4326 – WGS 84, for both layer and the project (checked in bottom right), and unit is thus in degrees. I add the layer world map (EPSG:4326 – WGS 84 by default) by taping “world” in the coordinate box in the middle bottom, I also add Open street map (EPSG:3857 – WGS 84 / Pseudo-Mercator by default) from XYZ Tiles. The polygons appear nicely on the map considering some are just adjacent to the nearby lake, many nicely adjacent to roads, etc.   When attempting to do buffers the distance is obviously set to degrees. I have tried to change the CRS, both for the layer(s) and the projects, but without luck. After researching (e.g. here: ) I believe that the correct CSR would be Arc 1960 / UTM zone 36S EPSG:21036 (it is my understanding that either 36N or 36S would work as the polygons appear both south and north of, but close enough to the equator). When setting the mentioned CRS for my polygon layer, the polygons disappear from the map, and remain gone even after setting the project CSR (by bottom right) to the same. It seems that whenever I try with different CRS in UTM, the layer doesn’t show. Does this mean that the polygons are somehow not compatible with units in meter? Is there an issue with importing the .prj file?  Other things I've tried:   I have made a good attempt searching for solutions. I have ensured that the polygon layer is on top of the layers list. I have ensured the file names are identical and tried all different suitable CRS I can think of. I have seen similar questions been solved by saving the .shp 'as', but I don't think that's my issue as it's already a .shp file. Can it be the case that I need to perform a datum transformation? I gave it a shot using a transformation code (1122) provided by above link, but then the polygons were projected on the Antarctica on the world map, so obviously something went quite wrong...   Note that when I have changed to what I believe is the right CRS I can execute buffers in units of meters, however, they do not appear on the window…
111538
I have slight experience with ArcGIS, but am new to QGIS.  I'm trying to set the projection of my map, and I understand that this is done by altering the CRS (coordinate reference system) of each layer and/or the entire project.  When I right click a layer and select "Change Layer CRS", however, the visual representation of the map (the distortion) does not reflect the selected projection. My world map looks like it has a Robinson (or similar) projection, even if I select a Mercator CRS. The EPSG code in the lower right corner changes, as do the coordinates.    Setting the project CRS to the same projection does not help, nor does enabling on-the-fly projection.  My goal is to export the map to SVG, so the visual distortions are important.  Am I doing something wrong?
22959
In answer to  Klas Karlsson puts forward a solution to the problem of formatting print composer grid labels for projected maps.  I'm very weak on scripting, but in QGIS 2.14 I've tried to enter the text as shown in Klas's illustration, which generates error messages. In my case I'm working with a coordinate system that has a six-digit Easting and a six-digit Northing and I'm trying to get a result similar to that shown in Klas's picture (but with a six-digit Northing). Can anyone help me with this?
74963
I am using QGIS v3.12 and projection EPSG:27700 - British National Grid.  I am trying to add a label to my map layout which will give the grid reference of the centre of the map as a UK 8 digit grid reference ( e.g. "AB123456" ).  So far I have managed to get the x and y coordinates using the expression:   Grid reference at map centre: [%round(x (map_get (item_variables('Map1'), 'map_extent_center')),0)%] , [%round(y (map_get (item_variables('Map1'), 'map_extent_center')),0)%]   Is there any function available in QGIS that can translate these coordinates into the required format?   Sorry my coding skills are not that great!
76218
I have a script which contains several r objects which are CRSs that I use for transforming spatial objects. After updating R and many packages, there is a warning which wasn't there before. LCC &lt;- CRS(&quot;+proj=lcc +lat_1=49 +lat_2=77 +lat_0=0 +lon_0=-95 +x_0=0 +y_0=0 +ellps=GRS80 +units=m +no_defs&quot;)  Warning message: In showSRID(uprojargs, format = &quot;PROJ&quot;, multiline = &quot;NO&quot;, prefer_proj = prefer_proj) :   Discarded datum Unknown based on GRS80 ellipsoid in CRS definition  I understand that this is due to a change in how spatial information is stored... PROJ4 to PROJ6 upgrade and &quot;Discarded datum&quot; warnings ..but beyond that, I don't understand what this error means or if I need to do anything in response. Any thoughts?
46752
I'm not much of a GIS user, but I've got a big ascii file that I'm trying to convert into a   lat  long  data x1   y1     d1 x1   y2     d2 x1   y3     d3 x2   y1     d4 ... etc   format, so that I can work with it in R.  I've got global national identifier data (i.e.: which country occupies what grid) at 2.5 arc-minute resolution, but I want to coarsen it into half-degree, because that is the resolution of the rest of my data.  I could do so in R if the file weren't so large -- its 3.9GB and I can't read it into memory.  A NetCDF file would obviously be ideal for me, but I can't find a netcdf version of the data I want.  The data is categorical -- country identifiers.  What I want to do is simple to take each 12x12 block of gridcells, evaluate that N=144 matrix, and return the country that appears the most times.  (I'd also like it to ignore NA values, unless all values are NA).  This would be easy enough in R if I could only open the darn text file.  So I opened QGIS, but there doesn't seem to be any obvious way to "coarsen" a raster.    Is there one?    Then it occured to me that I could convert the data to vector, and then convert it back to raster, specifying the resolution that I want.    BUT is there a way to do so that would allow me to specify that each gridcell should be .5x.5 degrees, going from -180 to 180 and -90 to 90?    This seems like a pretty gross hack.    Is there a better way?    I've decided that it makes more sense for me to just make the file into a netcdf using a remote machine with the memory for it.
81996
Trying to load and plot a raster (it's a DEM) in R, but having problems.    Using R I read in a raster file:  library(raster)  dem &lt;- raster("DEM_Victoria.tif")  # &gt;70 MB print(dem)  class       : RasterLayer  band        : 1  (of  3  bands) dimensions  : 5444, 6007, 32702108  (nrow, ncol, ncell) resolution  : 100, 100  (x, y) extent      : 176615.6, 777315.6, 5650397, 6194797  (xmin, xmax, ymin, ymax) coord. ref. : +proj=longlat +ellps=WGS84 +no_defs  data source : DEM_Victoria.tif names       : DEM_Victoria values      : 0, 255  (min, max)   My confusion here is the extent vs the CRS. The extent shows coordinates from a UTM Zone 55S system, while the CRS reports it as longlat.   Similarly, gdalinfo reports:  Driver: GTiff/GeoTIFF Files:  DEM_Victoria.tif Size is 6007, 5444 Coordinate System is: GEOGCS["GDA94",     DATUM["unknown",         SPHEROID["unretrievable - using WGS84",6378137,298.257223563]],     PRIMEM["Greenwich",0],     UNIT["degree",0.0174532925199433]] Origin = (176615.587999997427687,6194797.138000000268221) Pixel Size = (100.000000000000000,-100.000000000000000) Metadata:   AREA_OR_POINT=Area Image Structure Metadata:   COMPRESSION=LZW   INTERLEAVE=BAND Corner Coordinates: Upper Left  (  176615.588, 6194797.138) (Invalid angle,Invalid angle) Lower Left  (  176615.588, 5650397.138) (Invalid angle,Invalid angle) Upper Right (  777315.588, 6194797.138) (Invalid angle,Invalid angle) Lower Right (  777315.588, 5650397.138) (Invalid angle,Invalid angle) Center      (  476965.588, 5922597.138) (Invalid angle,Invalid angle) Band 1 Block=6007x1 Type=Byte, ColorInterp=Red Band 2 Block=6007x1 Type=Byte, ColorInterp=Green Band 3 Block=6007x1 Type=Byte, ColorInterp=Blue   Is this real? A problem? (well it is to me, but perhaps because I don't understand something) Fixable?  I tried 'Assign projection' in QGIS, which uses this command:  gdalwarp -t_srs EPSG:28355 -srcnodata -32768  DEM_Victoria.tif DEM_Victoria.tif.tmp   but it failed with:     ERROR 1: Too many points (12100 out of 12100) failed to transform,   unable to compute output bounds.
82980
I'm new to QGIS and tried importing  (stops.txt). The project CRS, base map CRS and GTFS CRS have all been set to Google Mercator, but the points that are supposed to appear in Boston is now plotted in the middle of the ocean.  Did I miss out on something that messed up the import/plotting?
81956
I have two raster datasets, they have different projected coordinate systems; one in WGS_84_UTM_Zone_N34, another in Hungarian_1972_EOV,  they overlap each other perfectly if I open them in QGIS.   I would like to transform the coordinate system of the first raster into the second.  I tried Project Raster tool in Data Management toolbox (ArcGIS), it converted the first raster into Hungarian_1972_EOV, but it doesn't overlap with the second raster perfectly (There is a shift between two raster datasets fo about 10-15 meters).   Can anybody help me to find out what is the problem?
54256
I am trying to extract the values of a multiband raster to a polygon in R. ACVheatingdegreedayS &lt;- stack(&quot;location/multibandraster.tif&quot;) ACVheatingdegreedayS &lt;- ACVheatingdegreedayS %&gt;%    projectRaster(ACVheatingdegreedayS, crs=&quot;EPSG:3035&quot;)  ( zCVhdd1 &lt;- CVheatingdegreedayS[[1]] )  I want to avoid that last line of code where I break the multiband into a single band. There are 70 bands, so creating separate rasters would be very time consuming. Anyone know of a way to extract all bands of a multiband raster to a polygon?
57233
I like to think I'm relatively well-versed in datums, projections, and coordinate reference systems.  OpenStreetMap data is stored in WGS84 Lat/Lon (EPSG:4326). This CRS is geographic and therefore intended to store locations on a 3D globe. When I see  what am I looking at?  Looking at Reykjavik it appears that the longitude lines are tending towards the North Pole at the Greenwhich Meridian (or maybe they planned the city in perspective view??) so I assume 0,90 is top-centre of the map.  Does this class as a projection, and if so which one?   Is there one projection that is commonly used for lat/lon data?  I have data stored in Oracle using EPSG:4326 and when rendered by GeoServer without a specified projection it also displays these characteristics.
73710
Can somebody please explain what is the difference between the Coordinate system (WGS 84 for example) and a Projection (Universal Transverse Mercator for example)?  What is the difference between a projected coordinate system and projected CRS
44745
I have been attempting to use the Spatial Analyst Curvature tool with mixed results.  I originally tried to use it with a raster that was projected using a 1983 Teale Albers projection and the results were black, indicating the lowest values.  I then transformed the raster into UTM projection and ended up with grid-like lines on the raster which have values that are obviously not accurate.  Does anyone know why these lines have appeared or what I'm doing wrong.  Thanks.
116049
Still learning my way around QGIS and ran into an odd issue this evening. I'm using a program called Radio Mobile Deluxe to generate RF models.  It exports images as KML ground overlays.  I then bring the KML into QGIS, then georeference the raster.  However, this evening, I noticed that things didn't look quite right.  I should be looking at perfectly square objects (8000x8000 meters and a 800x800 pixel raster).  The overlay imports perfectly into Earth, but when I bring it into QGIS, it's measuring out 10km wide.  However, when I compare visual features in the imagery basemap and roads, everything looks dead on.  I'm really not sure what I'm looking at here, if it's a problem, or how to fix it.  I'm using QGIS 2.18.4, the project CRS is 4326.  Not quite sure what other information I should provide.  Here's a screenshot, showing a very square object in Earth and a not-so-square object in QGIS, along with the N/S/E/W coordinates generated by Radio Mobile.    Here's a sample KML file I created in Earth and loaded into QGIS:  &lt;?xml version="1.0" encoding="UTF-8"?&gt; &lt;kml xmlns="http://www.opengis.net/kml/2.2" xmlns:gx="http://www.google.com/kml/ext/2.2" xmlns:kml="http://www.opengis.net/kml/2.2" xmlns:atom="http://www.w3.org/2005/Atom"&gt; &lt;Document&gt;     &lt;name&gt;foo.kml&lt;/name&gt;     &lt;Style id="s_ylw-pushpin_hl"&gt;         &lt;IconStyle&gt;             &lt;scale&gt;1.3&lt;/scale&gt;             &lt;Icon&gt;                 &lt;href&gt;http://maps.google.com/mapfiles/kml/pushpin/ylw-pushpin.png&lt;/href&gt;             &lt;/Icon&gt;             &lt;hotSpot x="20" y="2" xunits="pixels" yunits="pixels"/&gt;         &lt;/IconStyle&gt;         &lt;LineStyle&gt;             &lt;color&gt;ff0000ff&lt;/color&gt;             &lt;width&gt;3.5&lt;/width&gt;         &lt;/LineStyle&gt;         &lt;PolyStyle&gt;             &lt;fill&gt;0&lt;/fill&gt;         &lt;/PolyStyle&gt;     &lt;/Style&gt;     &lt;StyleMap id="m_ylw-pushpin"&gt;         &lt;Pair&gt;             &lt;key&gt;normal&lt;/key&gt;             &lt;styleUrl&gt;#s_ylw-pushpin&lt;/styleUrl&gt;         &lt;/Pair&gt;         &lt;Pair&gt;             &lt;key&gt;highlight&lt;/key&gt;             &lt;styleUrl&gt;#s_ylw-pushpin_hl&lt;/styleUrl&gt;         &lt;/Pair&gt;     &lt;/StyleMap&gt;     &lt;Style id="s_ylw-pushpin"&gt;         &lt;IconStyle&gt;             &lt;scale&gt;1.1&lt;/scale&gt;             &lt;Icon&gt;                 &lt;href&gt;http://maps.google.com/mapfiles/kml/pushpin/ylw-pushpin.png&lt;/href&gt;             &lt;/Icon&gt;             &lt;hotSpot x="20" y="2" xunits="pixels" yunits="pixels"/&gt;         &lt;/IconStyle&gt;         &lt;LineStyle&gt;             &lt;color&gt;ff0000ff&lt;/color&gt;             &lt;width&gt;3.5&lt;/width&gt;         &lt;/LineStyle&gt;         &lt;PolyStyle&gt;             &lt;fill&gt;0&lt;/fill&gt;         &lt;/PolyStyle&gt;     &lt;/Style&gt;     &lt;Placemark&gt;         &lt;name&gt;Untitled Polygon&lt;/name&gt;         &lt;styleUrl&gt;#m_ylw-pushpin&lt;/styleUrl&gt;         &lt;Polygon&gt;             &lt;tessellate&gt;1&lt;/tessellate&gt;             &lt;outerBoundaryIs&gt;                 &lt;LinearRing&gt;                     &lt;coordinates&gt;                         -79.22887,38.08849,0 -79.13737,38.08849,0 -79.13737,38.08849,0 -79.13737,38.16048,0 -79.22887,38.16048,0 -79.22887,38.16048,0 -79.22887,38.16048,0 -79.22887,38.08849,0                      &lt;/coordinates&gt;                 &lt;/LinearRing&gt;             &lt;/outerBoundaryIs&gt;         &lt;/Polygon&gt;     &lt;/Placemark&gt; &lt;/Document&gt; &lt;/kml&gt;   EDIT: Here's what the raster looks like (after converting to polygon and removing the background).    When I spot-check the overlay down to the pixel, it's identical between QGIS and Earth.  Accurate enough for modeling RF signals, which tend to get pretty fuzzy in the real world.
64290
I have raster displaying Lat/ Long grid, but map information shows that, it s been mapped in Gauss Krugger projetion/ Beijing 1954. So, technically we need to geo reference the map in Gauss Krugger/ Beigjing 1954 Projectec Coordinated System in ArcGIS.   So, basically what I need to do is, georeference raster by input of Lat/Long, but need to update the georeferencing by projected coordinated system mentioned above.  In Global mapper, we can load the raster and enter Lat/Long available in the map, straight away it will be recalculated to Projected coordinated system.   Can we get anything same in ArcGIS?