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I need to extract values to point features from Mosaic dataset made out of DEMs (Whole world SRTM) . My feature class has 18,000,00 points.

When I ran the below tools, only <20K points receive elevation values ,rest all are null though DEM at those location is not null.

Spatial Analyst

  • Extract Values to Points
  • Extract Multi Values to Points

3D Analyst

  • Add Surface Information

Per suggestions in https://community.esri.com/ , I ensured below. None seems to work .

  1. CRS of DEM and Feature Class is same
  2. Do not open the fc and moasic in ArcMap
  3. Use Spatial Analyst or 3D Analyst tools in Catalog
  4. Put FC and Mosaic Dataset in a common Geodatabase
  5. Run using ArcPy

Often I see claims of of this tool working after a relevant patch to 10.1 . I am using latest version 10.6 and seems to have no solution to this problem.

My production system is built on ArcMap so using ArcGIS Pro is not an option for me.

How the tool is executed ?

Tool Boxes > System Tool Boxes > Spatial Analyst Tools > Extraction > Extract Values to Points

Input point features --> D:\Data\Terrain.gdb\points
Input raster  --> D:\Data\Terrain.gdb\SRTM3
Output point features --> D:\Data\Terrain.gdb\points_elev

Environment of the ArcMap

OS : Windows 10
Virtual Technology : None
Webserver: None (using only desktop)
Service Pack: None
DBMS : File geodatabase (for storing Mosaic  dataset and feature class)
Virtual Technology : None
DBMS OS: Windows 10
DBMS Version: File Geodatabase

ArcPy Script

import arcpy
from arcpy import env
from arcpy.sa import *

# Set environment settings
arcpy.env.workspace = r"in_memory"
arcpy.env.overwriteOutput=True
arcpy.CheckOutExtension('Spatial')

# Set local variables
inPointFeatures = "D:\Data\Terrain.gdb\points"
inRaster = "D:\Data\Terrain.gdb\SRTM3"
outPointFeatures = "D:\Data\Terrain.gdb\points_elev"

# Execute ExtractValuesToPoints
ExtractValuesToPoints(inPointFeatures, inRaster, outPointFeatures,
                      "INTERPOLATE", "VALUE_ONLY")

What happens with subset of points ?

  • When we experimented with subset say - 600 points or 20,000 points - the same issue is seen. Some gets elevation values(correct values), the others have null values. Neither the toolbox nor the Arcpy script throw any error.

  • We noticed ,using one raster(Geotiffs on disk) at a time is giving us correct values. This is however taking 12 hours or more - not suitable for task at hand.

  • 1
    Do the extracted points have the correct elevations? You could also try building a virtual raster instead of/over the mosaic. I don't see how that would help but it's easy to test. – Jon Sep 27 '18 at 4:23
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    What are the precise steps that you perform, beginning with when you start ArcMap, when you see this failure? For any tools used what are the parameter values? – PolyGeo Sep 27 '18 at 4:56
  • 2
    Check your environment extent. – FelixIP Sep 27 '18 at 5:52
  • 1
    Does 18 lakh = 1,800,000? – user2856 Sep 27 '18 at 6:20
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    I don't believe you answered the question: are the subset of points returned actually correct? (Or were you saying they're only correct when you use "one raster"?) – Jon Sep 27 '18 at 14:19

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