GeoConverter

Fast, auditable coordinate conversion for:

• ITM (EPSG:2039) ↔ WGS84 (EPSG:4326)
• Web Mercator (EPSG:3857) ↔ WGS84 (EPSG:4326)

Designed for performance, transparency, and reproducibility.

Demo (interactive map + benchmarks)

Why GeoConverter?

Most projection libraries:

• are black boxes
• optimized for flexibility, not speed
• hard to audit mathematically

GeoConverter is:

• ⚡ Fast --- optimized for large coordinate batches
• 📐 Transparent --- math matches EPSG definitions step-by-step
• 🧪 Testable --- roundtrip + proj4 comparisons included
• 🧭 Deterministic --- no hidden state

Built for:

• GIS pipelines
• simulation
• mapping tools
• mobility & geo analytics
• visualization engines

Install

npm install @peterbak6/geoconverter

Usage

ITM (EPSG:2039)

import { toItm, fromItm } from "@peterbak6/geoconverter";

const [E, N] = toItm(35.503194, 32.547015);
const [lon, lat] = fromItm(E, N);

High-performance variant (no tuple allocation)

import { toItmOut } from "@peterbak6/geoconverter";

const out = new Float64Array(2);
toItmOut(lon, lat, 0, out, 0);

const E = out[0];
const N = out[1];

Web Mercator

import { toWebMercator, fromWebMercator } from "@peterbak6/geoconverter";

const [x, y] = toWebMercator(35.21, 31.77);
const [lon, lat] = fromWebMercator(x, y);

Accuracy

Validated against Proj4 using the official EPSG:2039 definition.

Metrics:

• forward delta vs proj4
• inverse delta vs proj4
• roundtrip drift

Example test points:

[34.7893, 32.0732]
[35.2134, 31.7683]
[34.9876, 32.1234]

Roundtrip drift is typically near floating-point precision.

Performance

Benchmarked for high-volume coordinate conversion.

Typical results (machine dependent):

WebMercator 1M: ~70 ms
ITM 1M:        ~380 ms
ITM (no tuple): ~320 ms

Focus:

• minimal allocations
• predictable memory
• vector-friendly math

Demo

Interactive site includes:

• live converter
• map hover showing Lon/Lat, WM, ITM
• accuracy comparison vs proj4
• performance microbenchmarks

→ https://peterbak6.github.io/geoconverter

Math transparency

Implements full pipeline:

• geodetic ↔ ECEF
• Helmert transform
• Transverse Mercator series
• EPSG parameters
• GRS80 ellipsoid

No hidden simplifications.

API

ITM

toItm(lon, lat)
fromItm(E, N)
toItmOut(lon, lat, flags, outArray, offset)

WebMercator

toWebMercator(lon, lat)
fromWebMercator(x, y)

All angles in degrees.
All projected units in meters.

Repository structure

packages/geoconverter
apps/demo

• npm library
• demo site (GitHub Pages)

Development

pnpm install
pnpm -C packages/geoconverter build
pnpm -F demo dev

License

MIT --- free for commercial and research use.