Horizontal and vertical accuracy assessments of digital surface model (DSM) and digital elevation model (DEM) data for the Colorado River corridor in Grand Canyon National Park and Glen Canyon National Recreation Area (2002, 2009, 2013 and 2021)

The horizontal accuracy assessment dataset consists of spatial coordinate and elevation values of “hard points” identified in each digital surface model (DSM) dataset and their spatial location data from the geodetic control network maintained by the U.S. Geological Survey (USGS), Grand Canyon Monitoring and Research Center (GCMRC). Surveyed “hard points” represent stationary natural features, such as corners of large boulders, that are visible in aerial imagery and elevation datasets and are in the geodetic control network maintained by the USGS, GCMRC. The vertical accuracy assessment dataset consists of pixel elevation values extracted from the DSM and digital elevation model (DEM) datasets for 926 “control points”. Surveyed "control points" represent survey marks and benchmarks in the geodetic control network maintained by the USGS, GCMRC. Each “hard point” and control point is denoted by a unique identifier from the Grand Canyon survey control network database maintained by the USGS, GCMRC. All point location are denoted by the distance upstream or downstream along the river channel from Lees Ferry, AZ. The temporal extent of the data is for the years 2002, 2009, 2013, and 2021, and the spatial extent is for the segment of the Colorado River riparian corridor from Glen Canyon Dam downstream to Pearce Ferry, AZ.