geojson-geometry

A robust, TypeScript-powered library for constructing and validating GeoJSON geometry objects, including support for all core GeoJSON types and circle extension.

Features

• Type-safe classes for Point, LineString, Polygon, MultiPoint, MultiLineString, MultiPolygon, and GeometryCollection
• Extended Circle geometry (as per Azure Maps/MapLibre conventions)
• Strict coordinate validation
• Factory methods for safe, declarative geometry creation
• Designed for modern JavaScript & TypeScript

Installation

npm install geojson-geometry

Usage

import GeoJSON from "geojson-geometry";

// Point
const point = GeoJSON.point([102.0, 0.5]);
console.log(point.toJSON());
console.log(point.toFeature());

// Circle
const circle = GeoJSON.circle([102.0, 0.5], 100);
console.log(circle.toJSON());
console.log(circle.toFeature({ name: 'Search Area' }));

// MultiPoint
const multiPoint = GeoJSON.multiPoint([
    [102.0, 0.5]
]);
console.log(multiPoint.toJSON());
console.log(multiPoint.toFeature());

// LineString
const lineString = GeoJSON.lineString([
    [102.0, 0.0],
    [103.0, 1.0]
])
console.log(lineString.toJSON());
console.log(lineString.toFeature());

// Polygon
const polygon = GeoJSON.polygon([
    [
        [100.0, 0.0],
        [101.0, 0.0],
        [101.0, 1.0],
        [100.0, 1.0],
        [100.0, 0.0] // polygon must close on first coordinates
    ]
]);
console.log(polygon.toJSON());
console.log(polygon.toFeature());

// GeometryCollection
const collection = GeoJSON.geometryCollection([ point, circle, multiPoint, lineString, polygon ])
console.log(collection.toJSON());

API

• All geometry classes provide .toJSON() and .toString()
• All geometry classes provide .toFeature(properties?) for GeoJSON Feature compatibility except GeometryCollection

Supported Geometry Types

Type	Coordinates Type	Notes
Point	[number, number]	Latitude, longitude
LineString	Array<[number, number]>	Sequence of positions
Polygon	Array<Array<[number, number]>>	Linear ring array
MultiPoint	Array<[number, number]>	Points array
MultiLineString	Array<Array<[number, number]>>	Lines array
MultiPolygon	Array<Array<Array<[number, number]>>>	Polygons array
GeometryCollection	Array<Geometry>	Heterogeneous Geometries
Circle (extension)	[number, number] + radius	Not standard GeoJSON

License

This project is licensed under the MIT License.

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© 2025 Harshal Khairnar, Hitraa Technologies.