Lidar GCPs were manually identify, extracted and measured in the following manner. First, we identiy distinctive terrain points throughout all of the frames comprising the photo block, at elevation ranging from sea level at the fjord edge to the highest peaks within the imagery and at as many points adjacent to the ice surface as possible. From this initial selection we were able to identify more than 200 potential GCP locations situated on stable topography such as bed-rock, rock outcrops and moraine structures.