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dem-3dep

USGS 3DEP bare-earth elevation for your US map regions, when you choose it

What it does

With hammunition station set --dem-source 3dep, downloads the USGS 3D Elevation Program's 1/3-arc-second (about 10 m) bare-earth tiles covering your US map regions from USGS's own bucket, checks each, and keeps them under /usr/local/share/hammunition/data/dem-3dep/; dem-qmapshack then draws QMapShack's hillshade, slope and contours from them instead of from Copernicus. With the default, copernicus, it fetches nothing.

Why you would want it

Copernicus GLO-30, the default, is a surface model: in forest it measures the treetops. Over a forested window in Shenandoah National Park it read 11.8 m above 3DEP on average (measured 2026-09-29), so its contours ride the canopy. 3DEP is the ground, at three times the resolution -- the elevation to want for a trail under trees.

Before it will work

Map regions set in station config, and dem_source set to 3dep. 3DEP covers the United States and its territories; a region elsewhere gets no 3DEP tile and the plan warns that QMapShack has no elevation for it while 3dep is chosen. Copernicus stays installed either way: BRouter's routing elevation reads it.

How it installs

  • elevation tiles from usgs-3dep for the regions in station config (Public domain (USGS), https://www.usgs.gov/information-policies-and-instructions/copyrights-and-credits)

Known problems

About ten times the size of Copernicus: a 3DEP tile is about 480 MB against Copernicus's 46 MB for the same square degree (Shenandoah one tile, Delaware two, about 0.9 GB, Vermont twelve, about 4.4 GB, measured 2026-09-29); the plan prints the size per region before anything downloads. Each tile is checked against the MD5 in the publisher's object metadata (its S3 ETag, carried in the list and asked for again before the download): "MD5 from the publisher's object metadata; not pinned by Hammunition", which catches a damaged download, not a deliberately altered one. Tile names encode latitude and longitude, so they are shown in the plan only. Switching dem_source back to copernicus removes the 3DEP tiles and redraws the contours from Copernicus on the next install.

Keeping it current

  • probe: none
  • strategy: reinstall
  • USGS replaces a tile in its current/ folder when new lidar arrives; the weekly check names a carried tile that changed, and the list is regenerated with scripts/gen_3dep_tiles.py --fetch.

Where to get help with the software itself

The 3D Elevation Program's pages (https://www.usgs.gov/3d-elevation-program) and The National Map's help desk for the data itself.

Source: catalog/packages/dem-3dep.yaml