Get Ground Height needs only three pieces of information - the matrix number, the X position and the Z position on the matrix that you want the height of:
Height# = Get Ground Height(MatrixNum,XPos,ZPos)
Height# then equals the height of the matrix at that position - regardless of the method for actually creating the matrix.
Use the X/Z position of the camera or player character object as the XPos and ZPos parameters and simply add the amount required to the returned value to place the camera/object in it's new position:
Position Camera Camera Position X(),Height#+2.0,Camera Position Z()
TDK_Man