https://community.esri.com/t5/developers-questions/getting-unexpected-georeferencing-after-raster/m-p/1267722#M6520 <P>Hi, I'm attempting to run a simple canopy height model (CHM) using a surface and bare-earth terrain model.&nbsp; I figured it would be quicker to do this in numpy, so I am using the RasterToNumPyArray methods in arcpy:</P><LI-CODE lang="python">import arcpy import os arcpy.CheckOutExtensions('Spatial') arcpy.env.overwriteOuptut = True datadir = 'D:/Data' dsm = os.path.join(datadir, 'dsm.tif') dtm = os.path.join(datadir, 'dtm.tif') arcpy.env.outputCoordinateSystem = dsm arcpy.env.cellSize = dsm dsm_arr = arcpy.RasterToNumPyArray(dsm, nodata_to_value=0) dtm_arr = arcpy.RasterToNumPyArray(dtm, nodata_to_value=0) diff_arr = dsm_arr - dtm_arr # Set things below 2m difference to 0 diff_arr[diff_arr &lt; 2] = 0 diff = arcpy.NumPyArrayToRaster(diff_arr, value_to_nodata=0) diff.save(os.path.join(datadir, 'diff.tif')) arcpy.CheckInExtension('Spatial')</LI-CODE><P>The result is that the diff.tif output is way off.&nbsp; The cell sizes are right, the SRS remains the same, and relatively speaking the values are correct (it's dropping negligible values I don't care about), but the georeferencing is off by thousands of miles.&nbsp; What am I doing wrong?&nbsp; Do I need to explicitly feed in a corner or extent?&nbsp; If so, how would I do that?</P> Tue, 14 Mar 2023 19:03:31 GMT EricEagle 2023-03-14T19:03:31Z https://community.esri.com/t5/developers-questions/getting-unexpected-georeferencing-after-raster/m-p/1267722#M6520 <P>Hi, I'm attempting to run a simple canopy height model (CHM) using a surface and bare-earth terrain model.&nbsp; I figured it would be quicker to do this in numpy, so I am using the RasterToNumPyArray methods in arcpy:</P><LI-CODE lang="python">import arcpy import os arcpy.CheckOutExtensions('Spatial') arcpy.env.overwriteOuptut = True datadir = 'D:/Data' dsm = os.path.join(datadir, 'dsm.tif') dtm = os.path.join(datadir, 'dtm.tif') arcpy.env.outputCoordinateSystem = dsm arcpy.env.cellSize = dsm dsm_arr = arcpy.RasterToNumPyArray(dsm, nodata_to_value=0) dtm_arr = arcpy.RasterToNumPyArray(dtm, nodata_to_value=0) diff_arr = dsm_arr - dtm_arr # Set things below 2m difference to 0 diff_arr[diff_arr &lt; 2] = 0 diff = arcpy.NumPyArrayToRaster(diff_arr, value_to_nodata=0) diff.save(os.path.join(datadir, 'diff.tif')) arcpy.CheckInExtension('Spatial')</LI-CODE><P>The result is that the diff.tif output is way off.&nbsp; The cell sizes are right, the SRS remains the same, and relatively speaking the values are correct (it's dropping negligible values I don't care about), but the georeferencing is off by thousands of miles.&nbsp; What am I doing wrong?&nbsp; Do I need to explicitly feed in a corner or extent?&nbsp; If so, how would I do that?</P> Tue, 14 Mar 2023 19:03:31 GMT https://community.esri.com/t5/developers-questions/getting-unexpected-georeferencing-after-raster/m-p/1267722#M6520 EricEagle 2023-03-14T19:03:31Z https://community.esri.com/t5/developers-questions/getting-unexpected-georeferencing-after-raster/m-p/1267763#M6521 <P>specify the lower left</P><P><A href="https://pro.arcgis.com/en/pro-app/latest/arcpy/functions/numpyarraytoraster-function.htm" target="_blank">NumPyArrayToRaster—ArcGIS Pro | Documentation</A></P><LI-CODE lang="python">pnt = arcpy.Point(LL_X, LL_Y) cell_size = # your cell size no_data = # your nodata value or None rast = arcpy.NumPyArrayToRaster(ai, pnt, cell_size, cell_size, no_data)</LI-CODE> Tue, 14 Mar 2023 20:07:11 GMT https://community.esri.com/t5/developers-questions/getting-unexpected-georeferencing-after-raster/m-p/1267763#M6521 DanPatterson 2023-03-14T20:07:11Z https://community.esri.com/t5/developers-questions/getting-unexpected-georeferencing-after-raster/m-p/1270358#M6534 <P>Thanks Dan, that did the trick.</P> Wed, 22 Mar 2023 13:29:40 GMT https://community.esri.com/t5/developers-questions/getting-unexpected-georeferencing-after-raster/m-p/1270358#M6534 EricEagle 2023-03-22T13:29:40Z