We investigated the effects of different GCP configurations
on DEM error by differencing each lidar point-controlled
photogrammetric DEM (summer 2003) from a DEM derived
solely from the lidar data. This gave a straightforward qualitycontrol
test whereby differences closest to zero represented
the best-quality DEM surfaces. We also examined the effects
of GCP configurations on estimates of glacier volume change
by computing differences between photogrammetric DEMs
(summer 2003) and a DEM derived from repeat survey
lidar data from summer 2005, and