feat: New @developmentseed/epsg package for shipping compressed EPSG code bundle

[kylebarron]

The full EPSG projection database, compressed to 309kb for the web.

Some existing EPSG amalgamations exist, but all are uncompressed, incomplete, outdated, and/or not reproducible ^{1 2 3 4}. This package uses the DecompressionStream API, now widely available in browsers, to bundle a gzip-compressed text file of WKT definitions for all 7352 defined EPSG codes.

Usage

Currently, the only package entrypoint is @developmentseed/epsg/all, which loads a Map<number, string>, with all EPSG definitions in OGC WKT2 format.

import loadEPSG from "@developmentseed/epsg/all";
import proj4 from "proj4";

// Load the EPSG database
const epsg = await loadEPSG();

// Access WKT strings by EPSG code.
const wkt4326 = epsg.get(4326);
const wkt3857 = epsg.get(3857);

// Then use proj4.js as normal
const converter = proj4(wkt4326, wkt3857);
const inputPoint = [1, 52];
const outputPoint = converter.forward(inputPoint);

Footnotes

1. epsg includes only 3912 definitions, stores older, deprecated proj strings, and is uncompressed, coming to 500kb. ↩

2. epsg-index stores extra parsed information for each projection and is 7.7 MB. ↩

3. proj4-list includes only 5434 definitions, stores older, deprecated proj strings, and is 759KB of uncompressed strings. ↩

4. @esri/proj-codes ships a lot of redundant information, coming to nearly 15MB of JSON. ↩

[kylebarron]

just noting that proj can be compiled to Wasm now: https://willcohen.github.io/clj-proj/