The Point Sample command samples Z values from a grid at any point. To perform the operation, create a data file with X and Y coordinates for the points you'd like to sample. See below for specifications on how to use the new objects and methods in automation: 

PointSample()

Syntax

Set Worksheet = object.PointSample(InGrid:="C:\Users\David\Downloads\Demogrid.grd", XYData:="C:\Users\David\Downloads\WellLocations.dat", XCol:=1, YCol:=3, ZCol:=4)

Remarks

This method will return the worksheet document that represents the original XYData file but with the new Z values (stored in StoreZCol) added. This worksheet being returned will be the same (or at least very close to the same) as the worksheet that is opened with the PointSample command in the UI.

Example 

Sub Main
	Dim Surfer As Object
	Set Surfer = GetObject(,"Surfer.Application")
	Surfer.Visible = True

	'use the default X, Y, and Z columns, which should be A, B, and D respectively
	Set Wks = Surfer.PointSample(Surfer.Path + "\Samples\Demogrid.grd", Surfer.Path + "\Samples\Demogrid.dat")

	'explicitly set the X, Y, and Z columns, which should now be B, C, and H respectively
	Set Wks2 = Surfer.PointSample(Surfer.Path + "\Samples\Demogrid.grd", Surfer.Path + "\Samples\Demogrid.dat", xCol:=1, YCol:=2, StoreZCol:=5)

	'make sure that the Worksheet Document being returned is valid
	Wks2.SaveAs("C:\Users\David\Downloads\zOutput.dat")
	Wks2.Close()
End Sub

Updated January 2021