Template for grid elevation model coordinate Transformations 1.0 Grid elevation model GridElevationModel This operation method is for a coordinate Transformation that implements an elevation model using grid elevation data. The elevation value for the input horizontal position shall be bilinear interpolated between the surrounding four grid points, and added to the input horizontal coordinates. 2 3 Grid Elevation Data GridElevationData The value of this operation parameter is the URL of a source of grid elevation data, in the 3D targetCRS of the coordinate Transformation that contains the value of this operation parameter. http://baesystems.com/DEM/TBD