geojson-equality-ts

geojson-equality-ts

Check two valid geojson geometries for equality.

This library is a fork of geojson-equality by Gagan Bansal (@gagan-bansal), ported to Typescript by Samir Shah (@solarissmoke). Published and maintained going forward by James Beard (@smallsaucepan).

Installation

npm install geojson-equality-ts

Usage

Use as either a class or function.

import { geojsonEquality, GeojsonEquality } from "geojson-equality";

// ... create g1 and g2 GeoJSON objects

geojsonEquality(g1, g2, { precision: 3 }); // returns boolean

const eq = new GeojsonEquality({ precision: 3 });
eq.compare(g1, g2); // returns boolean

In more detail.

const GeojsonEquality = require("geojson-equality");
const eq = new GeojsonEquality();

const g1: Polygon = {
    type: "Polygon",
    coordinates: [
      [
        [30, 10],
        [40, 40],
        [20, 40],
        [10, 20],
        [30, 10],
      ],
    ],
  },
  g2: Polygon = {
    type: "Polygon",
    coordinates: [
      [
        [30, 10],
        [40, 40],
        [20, 40],
        [10, 20],
        [30, 10],
      ],
    ],
  };

eq.compare(g1, g2); // returns true
const g3: Polygon = {
  type: "Polygon",
  coordinates: [
    [
      [300, 100],
      [400, 400],
      [200, 400],
      [100, 200],
      [300, 100],
    ],
  ],
};

eq.compare(g1, g3); // returns false

Options

precision number floating point precision required. Defualt is 17.

const g1: Point = { type: "Point", coordinates: [30.2, 10] };
const g2: Point = { type: "Point", coordinates: [30.22233, 10] };

geojsonEquality(g1, g2, { precision: 3 }); // returns false

geojsonEquality(g1, g2, { precision: 1 }); // returns true

direction boolean direction of LineString or Polygon (orientation) is ignored if false. Default is false.

const g1: LineString = {
    type: "LineString",
    coordinates: [
      [30, 10],
      [10, 30],
      [40, 40],
    ],
  },
  g2: LineString = {
    type: "LineString",
    coordinates: [
      [40, 40],
      [10, 30],
      [30, 10],
    ],
  };

geojsonEquality(g1, g2, { direction: false }); // returns true

geojsonEquality(g1, g2, { direction: true }); // returns false

compareProperties boolean when comparing features, take their properties into account. Default is true.

const g1: Feature<Point> = {
    type: "Feature",
    geometry: {
      type: "Point",
      coordinates: [30, 10],
    },
    properties: { foo: "bar" },
  },
  g2: Feature<Point> = {
    type: "Feature",
    geometry: {
      type: "Point",
      coordinates: [30, 10],
    },
    properties: { foo: "BAZZZZ" },
  };

geojsonEquality(g1, g2); // returns false

geojsonEquality(g1, g2, { compareProperties: false }); // returns true

Contributing

Once you run

npm install

then for running test

npm run test

to create build

npm run build

PRs are welcome.

License

This project is licensed under the terms of the MIT license.