I have a mesh ( with points and triangles that define it), and I will need to create a DEM model out of it ( in geotiff format if possible for space consideration, if not, then in ASCII grid format). I need the DEM for watershed and catchment delineation purpose.  Instead of using existing software like ArcGIS, I want to write my code to do it ( in C++ or C#), so that I can later integrate them into my own GIS software. is there anything in GDAL or other open source source code libraries that do this well? Or do I have to write from scratch?  PS:    there are a lot of posts like  on how to do it the other way round, ie: from DEM grid points to mesh, but they are not what I want.  I have a similar question as  on how to get DEM grid points from point clouds, but that is fundamentally different from this one. I don't need the mesh interpolation part for this question, as I already have the mesh. I can always create the bounding box for the mesh, loop through each grid points, get the z, and then construct the grid, but this is crude and can be slow. I'm unsure whether there is a faster way of doing it?
122551
I have a list of surveyor points, and I will need to create a DEM model out of it ( in geotiff format if possible for space consideration, if not, then in ASCII grid format).  I need the DEM for watershed and catchment delineation purpose.   Instead of using existing software like ArcGIS, I want to write my code to do it ( in C++ or C#), so that I can later integrate them into my own GIS software. is there anything in GDAL or other open source tools that do this well? Or do I have to write from scratch?
101528
I've got 1002 ~100 MB (5000'x5000') .tif files in a state plane (transverse merc) projection comprising a county-wide, 1-ft aerial dataset. After two days, gdal_merge.py is only at 93 of 1002. And when it's done, I'll still need to apply a mask/cutline, then reproject to EPSG:3857 before I can even start tiling. So I'm trying to find a quicker approach..  I'm relatively familiar with the VRT format and this idea of , but after several rounds of testing, I'm not convinced the workflow I'm pursing is more efficient.  Here's the workflow I'm asking about (skipping the mask/cutline for now):   gdalbuildvrt --> merge the 1002 .tif files -------------> outputs mosaic VRT gdalwarp -----> transform to EPSG:3857 ------------> outputs web merc VRT ..start tiling against the 2nd-generation VRT..   The tiling script I wrote in Python (which may be a weak-link in its own respects) is definitely capable of reading the VRT. Small-area windows render in a few seconds, still longer than I'd like. But large area windows take quite a long time. As I'm writing on this, I'm waiting on a sample z=12 tile to render.. I bet it's already eaten 20+ minutes.  Ultimately, my goal is to create 256x256 tiles in the OSM scheme, like you'd get out of Mapnik, but using a Python/GDAL-only approach. ..I've deemed this necessary because I can't get Mapnik to properly consume my 2nd-generation VRT.  My python script is creating the OSM grid properly---I sniped some code from a Mapnik utility (generate_tiles.;y), and I'm getting proper cell coordinates for my raster. But I question whether or not my ReadRaster() / WriteRaster() implementation is efficient.. I'll paste in that part; values are hard-coded for my sample z=12 tile..  def getTileData():     gdal.AllRegister()     dataset = gdal.Open('C:/xGIS/Aerial/3857/2009_1ft_od_3857.vrt', GA_ReadOnly)     bands = dataset.RasterCount     band_type = dataset.GetRasterBand(1).DataType      memDriver = gdal.GetDriverByName('MEM')     memDS = memDriver.Create("TEMP", 256, 256, bands, band_type, [])     memDS.SetGeoTransform( [94490, (256.0/(121069-94490)), 0, 96198, 0, 256.0/(96198-94490)] )      for b in range(1, bands+1):         s_band = dataset.GetRasterBand( b )         t_band = memDS.GetRasterBand( b )         data = s_band.ReadRaster( 94490, 69618, 121069, 96198, 256, 256, band_type )         t_band.WriteRaster( 0, 0, 256, 256, data )      createDriver = gdal.GetDriverByName('PNG')     createDS = createDriver.CreateCopy("C:/xGIS/RichlandCounty/Aerial/SCRich09_1ft/3857/tiles/snap_2.png", memDS)     createDS = None     memDS = None   Does anyone have any insights or reactions that might help me get results quicker?
9278
I have a raster (USGS DEM actually) and I need to split it up into smaller chunks like the image below shows. That was accomplished in ArcGIS 10.0 using the Split Raster tool. I would like a FOSS method to do this. I've looked at GDAL, thinking surely it would do it (somehow with gdal_translate), but can't find anything. Ultimately, I'd like to be able to take the raster and say how large (4KM by 4KM chunks) I would like it split up into.
106323
I have a DEM and I want to create a DTM from that DEM. Is it possible to do this in ArcGIS?
17297
I would like to use a Python script that is not based on arcpy to do things like  query a shapefile by attributes, create new layer from selection, and calculate areas of a polygon and convert polygons to points.  Anyone have any code examples of using other Python modules or libraries? I am able to do this easily using arcpy but i wanted to explore other options.
18796
I have a series of point clouds I want to convert to mesh (there are points inside the object, uniformly distributed, not only on the surface).  I want to generate a model of the surface of the point cloud.   When the model is convex (like a cube or a sphere) applying a convex hull around the object is good enough but when the model has holes (like a torus (a.k.a. doughnut)) or cavities (like the area around the eyes in a head model or the area around the steam in a glass of wine) those concave features are lost.  Is there a way to wrap a mesh around a point cloud in a "convex hull style" without loosing the cavities?  It doesn't need to be perfect, a reasonable approximation of the geometry of the object would be good enough.
47910
Hello to everyone again,  I'm looking for an addon or a short cut to fill fast and simmetrically a NOT FLAT surface that needs to be closed with vertices. Doing it manually it takes a lot of time. I tried to do CTRL F and then Grid fill,but it didn't work. Neither F key works. Check the attached screenshot. thanks.
22768
I am trying to clip or filter lidar files (.las, .xyz) using a shapefile that contains multiple polygons.  Is there open source software that can do this spatial operation?  My .las files are enormous, and I should say that I am very new to DEM data and analysis so any help would be very welcome.
86533
I'm new to QGIS and working with GIS in general (student of architecture), so please bear with me.  I have obtained shapefiles with topographic curves of an ocean floor. My intention is to export these as CAD files and render as 3D models of the ocean floor in Revit. I have done this procedure earlier with terrain shapefiles. My problem now is that these files mapping depth does not contain z values, so when exporting them into CAD they are completely flat rather than 3D models.  The depth information in meter exists as attributes in the file (see attached image). What I want is to transform this depth value into real z coordinates for each line so that the curves have different heights when importing as CAD file in Revit.  Thankful for any pointers in the right direction.
22240
Is it possible to use Delaunay triangulation to generate an image like the below from a raster or vector of an object (in this case, a human heart)? What software and techniques would be required to make something like this? My intention is to make and use something like this in Inkscape without having to draw all the nodes/lines/effects manually.
94922
I'm looking for a resource to figure out how to program a function to cut a 3d model in game.  Example: Enemy/NPC is sliced into 2 pieces with a sword. His body is not hollow, you can see bloody texture where normally a 'polygon hole' would be.   The first step is to actually 'cut/slice' the model, then add in polygons to fill the hole in the model. I know this can be done in 3D modelling software, but I'm not sure how to go about doing this in a game, code-wise. I do not wish to use 'pre cut-up" models, the code will determine where the cut is.  Any pointers in the right direction would be greatly appreciated.
19042
I have a large collection of points with X and Y coordinates in a projected coordinate reference system (EPSG:28992). I would like to compute a square buffer around it (say, 500 meters around the point), so I can crop this polygon with a raster layer (in TIFF format) and proceed with a further analysis with the values within the cropped windows.  I am aware that this is possible in , but for the sake of the workflow I am implementing, I prefer to have it entirely in the Python GDAL environment, so it becomes automatic. Since I know the X/Y coordinates and the size of the grid cells in the raster, I could add/subtract to the coordinates the desired buffer, but I wonder whether there is a less handcrafted version of this "square-buffer" operation, which is less prone to errors. Other Python libraries (e.g. shapely) would be fine for me as well.   Note that a band.GetRasterBand(1).ReadAsArray(X, Y, 5, 5) does not return the window around the point, but the window leaving the point in a corner.   For instance, the following code:  path_curr_lyr = r"path_to_tif_file" tif = gdal.Open(path_curr_lyr) dat = tif.GetRasterBand(1).ReadAsArray(9550, 9620, 1, 1) print(dat) sq_buf = tif.GetRasterBand(1).ReadAsArray(9550, 9620, 5, 5) print(sq_buf)   Accesses the raster grid cell X/Y (9550, 9620) and returning the value of forest coverage in that pixel, and the value of a window of width= 5 pixels.  &gt;&gt;&gt; [[44]] &gt;&gt;&gt; [[ 44  87  99  86  43]      [ 96  99  99  79  14]      [ 99  99  98  34   9]      [ 99  86  27  93  71]      [ 98  98 100  97  65]]    As you can see, this approach returns a window in which the "44" is not a central value, but one in the corner. I would like to have a procedure in which a window around the given grid cell coordinate is created.  Any advice on how to implement this?
32330
I have a new task where the client is asking for a .dwg file of layer labels. My first thought would be to create an annotation of the labels and then try and use the Export to CAD tool in ArcMap. Does this sound like an appropriate workflow?  I am using ArcMap 10.1  Ultimately I would like to create a model and tool to do this.
41338
I am digitising line-features based on WGS-84 point-coordinates from a PDF which cannot be copied from.  The final line layer should contain lines which each connect two points and have the following attributes:   Name of start point - name of end point value in [ft] value in [m] remark (same for all features) date of creation   Currently I have a csv-based point layer which simply contains the name and coordinates of each point.    Creating the point layer is no problem, but creating the lines is a bit of a hassle. Either I manually create a .csv containing all existing connections between points like the following table and run connect by lines:    Or I digitise the lines manually but fill in the values (except for the value in [ft]) automatically.    Personally I would prefer option 2, since option 1 involves more manual work and the process has to be repeated regularly (and I figure I could transfer the solution to other tasks), but I can't get the expression right which should fill in the name of the line. All other values are created flawlessly (though they are not taken from another layer based on geometry).  I added the WKT of each point to the point-layer. Currently I am running the following, which returns NULL, despite it seems to be correct to me:  attribute(get_feature('point-layer','geom',geom_to_wkt(start_point($geometry))),'Waypoint')||' - '||attribute(get_feature('point-layer','geom',geom_to_wkt(end_point($geometry))),'Waypoint')   Any ideas where I went wrong?
29211
I know nothing about Blender and I need to do a very simple 3D terrain with texture map.  I have a 1000 x 700 height map:   And I have a 1000 x 700 texture map:   And I want to combine them into a 3D model that I can view. I have done this before, about 8 years ago, in XNA but none of my old code will compile anymore under Visual Studio 2010.  I apologize that this is a very simple question. I'm not a CGI artist and I don't anything about Blender but I know that it can do this simple thing.  What are the steps to do this with Blender?  Thanks for posting the steps but I don't have Import -> images as planes. I just have this:   Am I in the wrong place? Thanks in advance!
107039
I currently have a mesh of a building (it has a texture). Initially it was a solid; however, I sliced off the top to remove noise in MeshLab. Now I have a mesh that's really only an outline. Any ideas how to fill it? I tried ALTF, but that didn't go very well.  An alternative hack would be to have a plane of the same shape, filled with a colour, and put inside (not sure how to do this either).   Thanks! Below is a screenshot of the mesh to show you what I mean.
32373
I want to try to make a simple 3D map for a small area (10 square miles) with some housing, some roads and some vegetation on it. My geodata is as follows:    shapes with houses/roads/vegetation.  LIDAR point cloud data over the area (can easily be built to a dem). georeferenced aerial image.   Any idea where to start to bundle these geodata together and make a neat looking 3D map?