Extract Z values of a raster layer to a point shapefile

Summary

Instructions provided describe how to extract Z values from a raster surface and write them into a point shapefile attribute table with the field calculator. In ArcGIS 9.0, the Spatial Analyst Geoprocessing Toolbox has a tool called Extract Values to Points, which produces the same output.

Procedure

1. Add the point shapefile and the surface to a map, making certain the point featureclass is listed first in the table of contents.
   
   

   Note:
   The point shapefile and raster must share the same coordinate system.

   
   
2. Add a numeric field to the point attribute table.
3. Right-click the new field heading > Calculate Values. Check the Advanced box.
4. In the pre-logic script edit box enter:
   
   

   Code:
   Dim pDoc As IMxDocument
   Dim pMap As IMap
   Dim pRLayer As IRasterLayer
   Dim pIdentify As IIdentify
   Dim pIDArray As IArray
   Dim pRIDObj As IRasterIdentifyObj
   Dim pPoint As IPoint
   Dim iPixelValue As Integer
   
   Set pDoc = ThisDocument
   Set pMap = pDoc.FocusMap
   Set pRLayer = pMap.Layer(1)
   Set pIdentify = pRLayer
   Set pPoint = New Point
   'Get point
   Set pNewPoint = [Shape]
   Set pIDArray = pIdentify.Identify(pNewPoint)
   If Not pIDArray Is Nothing Then
       Set pRIDObj = pIDArray.Element(0)
       'Get the value of the RasterIdentifyObject and add it to the field
       iPixelValue = pRIDObj.Name
   End If

   
   
5. In the '<new fieldname> =' box enter:
   
   

   Code:
   iPixelValue

   
   
6. Click OK and the raster Z values are added to the attribute field.