shapefile-wasmESRI Shapefiles, in the browser

Read and write shapefiles from GeoJSON — no server round-trip, no GDAL. A Rust core compiled to WebAssembly, with a small typed API in front of it.

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Live demo

API reference

View on GitHub

Both directions

GeoJSON to .shp/.shx/.dbf/.cpg/.prj, and all the way back again — including the ring re-nesting a shapefile's flat ring list makes necessary.

Runs anywhere

Browser, Node, and workers from one import. DOM helpers live behind a separate entry point, so the core is safe in SSR.

Correct by construction

dBase column widths are measured from your data rather than guessed, so long values are never silently cropped into different numbers.

Projections included

116 EPSG definitions — US UTM zones, NAD83 State Plane, the global basics — loaded on demand. No network call at runtime, ever.

Zero configuration

The WebAssembly binary ships embedded. Nothing to copy, serve, or teach your bundler about. A slim entry point is there when you want to stream it.

Typed and documented

Full TypeScript types with TSDoc on every public function, so your editor explains the format's sharp edges as you use it.

Try it

import { writeShapefileZip, readShapefileZip } from '@crmackey/shapefile-wasm';

const zip = await writeShapefileZip(
  {
    type: 'FeatureCollection',
    features: [
      {
        type: 'Feature',
        geometry: { type: 'Point', coordinates: [-93.265, 44.9778] },
        properties: { name: 'Minneapolis', pop: 429954 },
      },
    ],
  },
  { fileName: 'cities', epsg: 26915 },
);

const [layer] = await readShapefileZip(zip);
layer.geojson.features[0].properties.name; // "Minneapolis"

Why this exists

A shapefile is not one file. It is a .shp of geometry, a .shx index, a .dbf attribute table in a 1980s database format, and a .prj of projection text — all of which have to agree with each other. Getting that wrong produces files that open fine in one GIS and misbehave in another, usually without saying so.

This package leans on two well-tested Rust crates, shapefile and dbase, and handles the parts that are easy to get subtly wrong. Read more →