4 ms·

The USGS provides exactly what the author was looking for, free of charges, no computation required, no download required: https://elevation.nationalmap.gov/ar

The USGS provides exactly what the author was looking for, free of charges, no computation required, no download required: https://elevation.nationalmap.gov/arcgis/services/3DEPElevation/ImageServer/WMSServer https://elevation.nationalmap.gov/arcgis/services/3DEPElevat... Preview in QGIS: https://ibb.co/B5T49YBj https://ibb.co/B5T49YBj

jvanderbot 1y ago
Yeah the moment you reach for pixel level processing tricks in GIS you need to pause and rtfm. Grade calculations are right in qgis docs and part of their lessons, and are also top Google hits. https://docs.qgis.org/3.40/en/docs/training_manual/rasters/terrain_analysis.html https://docs.qgis.org/3.40/en/docs/training_manual/rasters/t... Even better, you'll learn about DEMs vs topo maps.
avidphantasm 1y ago
For more advanced terrain analysis, see GRASS GIS (https://grass.osgeo.org/ https://grass.osgeo.org/). It’s a but clunky, but accessible from QGIS via a plugin. Whitebox also has some nice terrain analysis tools (https://www.whiteboxgeo.com/ https://www.whiteboxgeo.com/).