node-point

A JavaScript/TypeScript library for handling Point geometry according to OGC (Open Geospatial Consortium) standards.

Features

• Create and manipulate Point geometries
• Support for WKT (Well-Known Text) format
• Geometric transformations including translation, scaling, and rotation
• Matrix-based transformations
• TypeScript support with full type definitions

Installation

npm install node-point

Usage

Basic Usage

import { Point, create, clone } from 'node-point';

// Create a new Point
const point = create();
point.coordinates = [-100, 40];

// Clone a point
const clonedPoint = clone(point);

Working with WKT

import { Point, fromWKT } from 'node-point';

// Create point from WKT format
const point = new Point();
fromWKT(point, "POINT(116.36 39.90)");
console.log(point.coordinates); // [116.36, 39.9]

Geometric Transformations

import { Point, translate, scale, rotate, transformMat3 } from 'node-point';

const point = new Point();
point.coordinates = [10, 10];

// Translation
translate(point, point, [5, 5]); // Moves point to [15, 15]

// Scaling
scale(point, point, [2, 2], [0, 0]); // Scales by factor of 2 around origin

// Rotation
rotate(point, point, Math.PI / 2, [0, 0]); // Rotates 90 degrees around origin

// Matrix transformation
const matrix = new Float32Array([1, 0, 0, 0, 1, 0, 10, 20, 1]);
transformMat3(point, point, matrix); // Applies transformation matrix

API Reference

Point Class

The main Point class representing a point geometry with the following properties:

• type: String - Always 'Point'
• coordinates: Array - [x, y] coordinates

Functions

create(): Point

Creates a new empty Point object.

clone(a: Point): Point

Clones a Point object.

fromWKT(out: Point, wkt: string): void

Parses a Point from WKT format string (e.g., "POINT(116.36 39.90)").

transformMat3(out: Point, a: Point, mat3: Float32Array): Point

Transforms a Point using a 3x3 matrix transformation.

translate(out: Point, a: Point, dxdy: number[]): Point

Translates a Point by dx and dy distances provided as an array.

scale(out: Point, a: Point, scale: number[], origin: number[] = [0, 0]): Point

Scales a Point by scale factors around an origin point.

rotate(out: Point, a: Point, rad: number, origin: number[] = [0, 0]): Point

Rotates a Point by radians around an origin point.

Data Format

Point Structure

{
  "type": "Point",
  "coordinates": [-100, 40]
}

WKT Format Support

Supports parsing POINT type WKT format:

POINT(116.36 39.90)

License

MIT