Architecture

crates/terrio        the library
  dataset.rs         open, read and write; format detection; fixes applied after reading
  formats.rs         the driver registry, with GDAL's short names
  drivers/           terrio's own raster drivers; drivers/vector/ its vector drivers
  geotiff.rs, cog.rs GeoTIFF tags and decoding, lazy window and overview reads
  vfs.rs             locations: paths, URLs, s3://, gs://, az://, zip archives, /vsi prefixes
  http.rs, s3.rs     range requests with a block cache; AWS Signature Version 4
  crs.rs             parsing, identification and transformation of coordinate systems
  ops/               translate, warp, mosaic, vrt, vector filters and SQL, rasterize, polygonize
  memory.rs          datasets from and to bytes
  info.rs            summaries
crates/terrio-cli    the terrio command
python/              Python bindings (PyO3, NumPy)
js/                  WebAssembly bindings (wasm-bindgen)
scripts/             test data, comparisons with GDAL, benchmarks

Data model

Rasters are held as wbraster::Raster: typed pixel buffers, band after band and row after row, with the georeferencing and CRS. RasterDataset adds the driver and whether nodata is declared. GeoTIFFs can also be opened lazily, to read windows and overviews without loading the image.

Vector datasets are wbvector::Layers: features with OGC simple-feature geometries (with Z and M), typed attributes and a schema.

Building on whitebox_next_gen

The wbraster, wbvector and wbprojection crates supply the data model, many codecs and the projection engine. Testing them against GDAL found codecs that decoded wrong pixels or lost georeferencing, so terrio has its own drivers for GeoTIFF, JPEG 2000, Zarr, netCDF, HFA, GeoPackage tiles, the Esri formats, FlatGeobuf, CSV, GeoJSON, GeoParquet, GML, GPX, KML, TopoJSON, MapInfo, OSM and shapefile writing. Upstream bugs are listed in the pull requests that replaced them.

Pure Rust

There are no C dependencies apart from the Zstandard codec, which compiles for WebAssembly too. JPEG 2000 uses a Rust port of OpenJPEG that is native only.