rwarp

rwarp is GDAL's warp pipeline in Rust: coordinate transforms, approximate transforms, source window planning and resampling kernels, with no runtime GDAL dependency. It follows GDAL's algorithms closely, written with reference to the GDAL source and checked against gdalwarp output, but it is an independent implementation, not affiliated with or endorsed by the GDAL project.

Try it in the browser: the demo warps web map tiles into a projection of your choice, client-side, compiled to WebAssembly.

Why another warper

GDAL's warper bundles planning, reading, coordinate mapping and resampling into one operation. rwarp separates them, so you can see and control what will be read before any pixel is touched:

target grid
    |
    v
[plan]  plan_chunks / compute_source_window
    |     which chunks, and which source pixels does each need?
    |     inspectable, serialisable, resumable
    v
[read]  the caller fetches bytes: COG tiles, Zarr chunks, byte-reference stores
    |
    v
[warp]  warp(): nearest, bilinear, cubic, lanczos, average, mode

That makes it a building block for caches, tile servers, browser viewers and planners that need to know the I/O cost of a reprojection up front.

What it covers

CRS transforms go through a small trait with two backends: libproj (the default, full PROJ) or proj4rs (pure Rust, builds for wasm32-unknown-unknown). See Getting started.

Status

Early development: the API will change. Each component is validated against GDAL output; the GDAL parity page lists what has been checked, how, and where rwarp deliberately differs. Feedback and testing are very welcome, at github.com/hypertidy/rwarp.