topic Re: Strange no data values -3,4028234663 in ArcGIS Spatial Analyst Questions

Strange no data values -3,4028234663

GIS_Administratorat_RWE — Thu, 17 Dec 2015 14:29:01 GMT

Hi,

when interpolating points to raster using arcpy I get strange values (-3,4028234663) for no data pixels. If I interpolate the same points with same method in Desktop I get NoData values. How could I get rid of these strange values and just have the "no data"? Any ideas?

Thanks a lot

Felix

Re: Strange no data values -3,4028234663

DanPatterson_Retired — Thu, 17 Dec 2015 14:47:45 GMT

Your code would be useful and what environments you set within your code to control the results

Re: Strange no data values -3,4028234663

GIS_Administratorat_RWE — Fri, 18 Dec 2015 07:51:09 GMT

Hi Dan,

I use the following lines to compile the interpolate from point features I have created from txt using

...

arcpy.ASCII3DToFeatureClass_3d(inTXT, inFormat, outFC, outType, zFactor, CS, inputRes, fileSuffix, decSep)

arcpy.AddZInformation_3d(outFC, "Z", "NO_FILTER") ==> outFC is the point FC

arcpy.env.mask=outFC
arcpy.env.nodata="NONE"

     # --- Interpolate surface
     outSurfaceTile = OUTRASTERWSP + str("/SPLINE_") + fClass + ".tif"
     outSurface = arcpy.sa.NaturalNeighbor(outFC,"Z",inputRes)
     outSurface.save(outSurfaceTile)

     arcpy.CalculateStatistics_management(outSurfaceTile)
     arcpy.BuildPyramids_management(outSurfaceTile) ==> this output shows the strange no data values
     outHS = OUTRASTERWSP + "/HS_" + fClass + ".tif"
     outHillshade=arcpy.sa.Hillshade(outSurface,135,45,"NO_SHADOWS")
     outHillshade.save(outHS) ==> this output shows nodata as no data values
     arcpy.BuildPyramids_management(outHS)

The strange thing is, that the only the result of the interpolation shows the strange values and the hillshade compile from that shows the normal "nodata" as no data values..

Thanks

Felix

Re: Strange no data values -3,4028234663

DanPatterson_Retired — Fri, 18 Dec 2015 08:16:11 GMT

perhaps it is the explicit setting of arcpy.env.nodata NoData (Environment setting)—Help | ArcGIS for Desktop since it doesn't seem to affect final results and things are as they should be when done through arcmap, I would see what removing or changing the settings on this has

Re: Strange no data values -3,4028234663

GIS_Administratorat_RWE — Fri, 18 Dec 2015 08:37:04 GMT

Hi Dan,

I have started without this env. setting - doesn't work as well..

Cheers

Felix

Re: Strange no data values -3,4028234663

DanPatterson_Retired — Fri, 18 Dec 2015 08:45:21 GMT

before after you deleted pyramids and statistics? once they are created, they should be removed before trying something else

Re: Strange no data values -3,4028234663

curtvprice — Wed, 30 Dec 2015 06:34:44 GMT

I would try saving to Esri grid format instead of .tif first.