SRTM to Mapbox Terrain-RGB

'Documenting' converting SRTM .dt2 files to Mapbox's Terrain RGB Raster DEM format for 3D views in Mapbox JS v2 / Mapbox Android v10 without using Mapbox's servers

To make it extra painful this was done on Windows 10.

Need

• Python
• GDAL
• Rasterio
• Rio-RBGify (its broken, use the fork or fix it tmnnrs/terrain-rgb#3)

Process

C:\Program Files\GDAL has the utilities needed cmd needs to be run from here or this added to path.

Get list of dt2 files

dir /b /s *.dt2 >dt2_list.txt

Build virtual set

gdalbuildvrt -input_file_list "C:\Users\user\Desktop\Raster DEM\dt2_list.txt" "C:\Users\user\Desktop\Raster DEM\uk.vrt"

Translate virtual set to geotiff

gdal_translate -of GTiff "C:\Users\user\Desktop\Raster DEM\uk.vrt" "C:\Users\user\Desktop\Raster DEM\translated.tif"

Warp WGS 84 EPSG 4326 to web mercator

gdalwarp -s_srs EPSG:4326 -t_srs EPSG:3857 -srcnodata -32767 -dstnodata 0 -r lanczos -wo SOURCE_EXTRA=1000 -co COMPRESS=LZW "C:\Users\user\Desktop\Raster DEM\translated.tif" "C:\Users\user\Desktop\Raster DEM\translated_mercator.tif"

Create mbtiles with RGB (should definitely use webp not png in future, Mapbox do..)

rio rgbify -b -10000 -i 0.1 --max-z 12 --min-z 0 --format png "C:\Users\user\Desktop\Raster DEM\translated_mercator.tif" "C:\Users\user\Desktop\Raster DEM\uk-rgb-dem.mbtiles"

Helpful

• Installing Python and GDAL https://github.com/PratyushTripathy/python_gdal_automated_windows
• Installing Rasterio and GDAL rasterio/rasterio#1963
• Most of the end result script https://github.com/tmnnrs/terrain-rgb
• The first person to get it working mapbox/rio-rgbify#19