GeoJSON

This dual-purpose library creates GeoJSON according to RFC 7946 in NodeJS as well as directly in your browser.

It contains all of the basic object types of GeoJSON geometries:

• GeoJson.Point and GeoJson.MultiPoint
• GeoJson.LineString and GeoJson.MultiLineString
• GeoJson.Polygon and GeoJson.MultiPolygon
• GeoJson.GeometryCollection

…and organizational objects:

• GeoJson.Feature
• GeoJson.FeatureCollection

Why do we need classes to build JSON objects?

• It makes some of the data types of GeoJSON more accessible, as some types like coordinates are just ordered arrays. Now you have named parameters.
• Working with typed objects allows to see how the objects can be combined.
• Adding properties to Feature is improved.

Installation

Either download the dist/index.js to a sensible location in your web project, or do a NPM installation:

npm install @fboes/geojson --save

Instead of a local installation you may also load the library from https://unpkg.com/. Beware: This makes https://unpkg.com/ a dependency of your project and may pose data protection issues.

<script type="module" src="https://unpkg.com/@fboes/geojson@latest/dist/index.js"></script>

Everything required for the functionality of this library is contained in dist/index.js.

Usage

Loading the library prior to use:

// 1. NodeJS - NPM installation
import GeoJson from "geojson";

// 2. Local installation and/or browser usage
import GeoJson from "dist/index.js";

Now you are set to build your GeoJSON:

const featureCollection = new GeoJson.FeatureCollection([
  new GeoJson.Feature(new GeoJson.Point(1.53946, 51.04571), {
    title: "Sailing boat",
    "marker-symbol": "harbor",
  }),
  new GeoJson.Feature(new GeoJson.Point(6.5664576, 58.109285), {
    title: "Lighthouse",
    "marker-symbol": "lighthouse",
  }),
]);

console.log(JSON.stringify(featureCollection));

which yields GeoJSON:

{
  "type": "FeatureCollection",
  "features": [
    {
      "type": "Feature",
      "geometry": { "type": "Point", "coordinates": [1.53946, 51.04571] },
      "properties": { "title": "Sailing boat", "marker-symbol": "harbor" }
    },
    {
      "type": "Feature",
      "geometry": { "type": "Point", "coordinates": [6.5664576, 58.109285] },
      "properties": { "title": "Lighthouse", "marker-symbol": "lighthouse" }
    }
  ]
}

Further readings

• simplestyle-spec: A simple specification for styling GeoJSON data.
• Maki Icons: Maki is an icon set made for map designers. Maki includes icons for common points of interest like parks, museums, and places of worship.
• Mapbox GeoJSON integration: This example adds GeoJSON data from an external file and uses it in a layer on the map.

Status

Legal stuff

Author: Frank Boës

Copyright & license: See LICENSE.txt