Terrain illustration credits

Regional elevation: Mapzen / Tilezen Terrain Tiles, hosted by AWS Open Data.
https://registry.opendata.aws/terrain-tiles/
Global GMTED2010 and SRTM terrain data courtesy of the U.S. Geological Survey.
Global ETOPO1 terrain data: DOC/NOAA/NESDIS/NCEI, National Centers for Environmental Information, NOAA, U.S. Department of Commerce.
The incorporated U.S. Government terrain data are not subject to copyright protection within the United States.
Provider attribution and source terms:
https://github.com/tilezen/joerd/blob/master/docs/attribution.md

Modifications: cropped regional coverage, bilinear resampling, artistic height and width exaggeration, directional shading and point-cloud rendering. Photo-guided summit shapes are blended into the regional terrain. These modifications are not approved or endorsed by USGS. This illustration is not suitable for navigation or measuring summit terrain.
Geographic outlines: Natural Earth, public domain.

Rebuild input (not loaded by site visitors):
Cache Terrarium PNG tiles at archive/terrain/5-{x}-{y}.png, x=22..25, y=10..14.
https://s3.amazonaws.com/elevation-tiles-prod/terrarium/5/{x}/{y}.png
Run scripts/build-atlas.py with Python, Pillow and NumPy.