Slope represents the change of elevation over a specific area.
LF 2020 Update Slope Degree (SlpD) and Slope Percent Rise (SlpP) products are generated from 1 arc-second Digital Elevation Models (DEM) tiles (approximately 30 meter) downloaded November 9, 2021 from The National Map (TNM) Viewer (v2.0), part of the USGS 3D Elevation Program (3DEP) which provides the best available public domain raster elevation data of the conterminous United States (CONUS), Alaska, Hawaii, and insular areas.
See metadata by extent for specific details regarding coordinate system and projection information.
Note:LF 2020 topographic products are consistently calculated from true north, a correction from earlier topographic products where Aspect was calculated incorrectly. Users are advised to download the LF 2020 topographic products for CONUS, HI, AK, and PRVI to replace LF topographic products previously downloaded. We also advise that LCP files created from earlier topographic products be re-created using the LF 2020 topographic products.
LF 2016 Remap and beyond includes a 90-kilometer buffer along the 1,500 miles of the eastern and southern borders AK shares with Canada. Then with the LF 2020 update, and future updates, for the Conterminous United States (CONUS) a 90-kilometer buffer into Mexico is also included.