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What is the vertical accuracy of the seamless 3DEP DEMs?
The most recently published figure of absolute vertical accuracy of the seamless DEMs within the conterminous United States, in terms of the National Standard for Spatial Data Accuracy (NSSDA) at 95% confidence level, is 3.04 meters. It is important to note, however, that the vertical accuracy actually varies significantly across the U.S. because of differences in source quality, terrain relief, land cover, and other factors. Details of this analysis are published in Accuracy Assessment of the U.S. Geological Survey National Elevation Dataset, and Comparison with Other Large-Area Elevation Datasets—SRTM and ASTER: U.S. Geological Survey Open-File Report 2014–1008.