Use georaster to read elevation data from GeoTIFFs in pure Rust.
This is really early work, but can already be used in A/B Street to calculate the height at intersections. This approach possibly replaces elevation_lookups, a much more flexible Python and GDAL-based solution. Those dependencies are quite heavyweight and have portability problems, even with Docker.
The approach in this repo is to stay as simple as possible, and only handle GeoTIFF files in EPSG:4326, so that no dependencies are needed for coordinate projection. In practice for A/B Street, once a DEM has been located, we have to do a bit of manual work to use it anyway, so those steps can very much include a one-time coordinate transformation.
Right now I've used this for only two sources.
- King County 2016 LIDAR, from ftp://ftp.coast.noaa.gov/pub/DigitalCoast/raster2/elevation/WA_King_DEM_2016_8589/kingcounty_delivery1_be.tif, in ESRI:103565.
- I've converted by doing
gdalwarp -t_srs EPSG:4326 input.tif output.tif, but there's room for improvement
- I've converted by doing
- Ordnance Survey Terrain 50 for the UK, cached at http://abstreet.s3-website.us-east-2.amazonaws.com/dev/data/input/shared/elevation/UK-dem-50m-4326.tif and originally processed by mem48