EarthDEM

Polar Geospatial Center (PGC) EarthDEM provides high-resolution Digital Surface Models (DSM) in non-polar regions at 2-meter spatial resolution. EarthDEM covers land surface between 60 degrees N and 60 degrees South excluding Alaska, Greenland, and the Kamchatka Peninsula. Polar data is openly available and can be found at REMA (Reference Elevation Model of Antarctica) and ArcticDEM . New areas will be released as new data acquisition gives sufficient coverage. Individual Digital Surface Models (DSM) can be used to provide measurements of elevation change through time. EarthDEM products are constructed using many thousands of individual stereoscopic Digital Elevation Models (DEM) extracted from pairs of submeter (0.32 to 0.5 m) resolution DigitalGlobe (Maxar) satellite imagery. Source imagery is from WorldView-1, WorldView-2, and WorldView-3, and a small number from GeoEye-1, acquired between 2009 and the present (2021). EarthDEM is available as both original “strip” DEMs that preserve the original source imagery acquisition dates and temporal characteristics, as well as mosaic tiles compiled from multiple strips in a median-style mosaicking method. The time-dependent nature of the strip DEM files allows users to perform change detection analysis and to compare observations of topography data acquired in different seasons or years. EarthDEM Release 1 includes limited areas to gather feedback on product format and usability. Products include 50 km x 50 km mosaic tiles and strip DEMs, both at 2-meter resolution. Future work will target improved water masking, DEM registration to a reference elevation dataset, and improved quality assessment tools. For both strips and mosaics, an Esri shapefile is available as an index (footprint polygons), compatible with most GIS software. Unlike the REMA and ArcticDEM datasets, download links are not included as an attribute. Data will be available for download (after eligibility verification) through the NASA Smallsat Data Explorer . EarthDEM strip and mosaic files are projected in a local UTM zone (units: meters) depending on location and based on the WGS84 datum. Vertical reference is height above the WGS84 ellipsoid.