Add start and end z-values to a line feature using Python script

Summary

There is no direct way to insert the start and end elevation of a line feature as attribute values. The Interpolate Shape tool can only add z-values to the feature geometry, and the Add Surface Information tool can only add the mean elevation of a feature by defining the elevation surface. However, it is possible to add the start and end z-values to a line feature as attribute values by combining the Interpolate Shape tool and a Python script.

Procedure

The instructions provided describe how to add start and end z-values to a line feature.

1. Run the Interpolate Shape tool to add the z-values vertices to the desired line features. Input the elevation data into the Input Surface field, and select the desired line feature from the Input Feature Class drop-down.
   
   
    
2. Open the attribute table of the newly created line feature, and add two new fields with Float or Double data type for the start and end z-values. For more information on adding fields, refer to the following web help document, ArcGIS Desktop: Adding fields.
   
   
    
3. Run the following script through the Python console (Geoprocessing > Python.)
    

   import arcpy
   
   #Specify the desired workspace.
   input_fc = r'<workspace>\<line_feature>'
   
   #Modify this part according to the specified field names created in step 2.
   myfield1 = "Z_Start"
   myfield2 = "Z_End"
   myshape = "SHAPE@"
   
   #Iterate between rows available in the attribute table of the line feature and input the z-values.
   with arcpy.da.UpdateCursor(input_fc, (myshape, myfield1, myfield2)) as cursor:
       for row in cursor:
           geom = row[0]
           startpt = row[0].firstPoint
           endpt = row[0].lastPoint
           row[1] = round(startpt.Z, 2)
           row[2] = round(endpt.Z, 2)
           cursor.updateRow(row)

   
   
    
4. The result is populated in the two new fields created in Step 2.