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A modular toolkit for working with geographic data.


The Terraformer project is broken up into a series of smaller modules.

  • Terraformer Core - Contains methods and objects for working with GeoJSON. This also contains common methods used by other modules.
  • WKT Parser - Parse Well Known Text into GeoJSON and vice versa.
  • ArcGIS Geometry Parser - Parse the ArcGIS Geometry Format into GeoJSON and vice versa.
  • GeoStore - A framework for persisting and querying GeoJSON features with pluggable indexes and persistent stores.


  • Designed to work in Node and the browser
  • No dependencies on other tools or libraries

Getting Started

Check out the getting started guide which will give you an overview of core concepts and methods in Terraformer.


Install the core module with npm and then require it in your Node program.

$ npm install terraformer
var Terraformer = require('terraformer');

If needed, supporting packages can be added too.



To see Terraformer in action in the browser, check out our live demos. To use it in the browser yourself, reference it using a <script> tag.

<script src="[email protected]"></script>

To utilize supporting packages, you must load their source as well.

<script src="[email protected]"></script>
<script src="[email protected]"></script>


Make sure you check out the full documentation on the Terraformer website and the getting started guide.

var polygon = new Terraformer.Primitive({
  "type": "Polygon",
  "coordinates": [
      [-122.665894, 45.5229015],
      [-122.669263, 45.5229165],
      [-122.671151, 45.5184062],
      [-122.673254, 45.5140008],
      [-122.668426, 45.5127378],
      [-122.667654, 45.5169478],
      [-122.665894, 45.5229015]

var point = new Terraformer.Primitive({
  "type": "Point",
  "coordinates": [-122.669477, 45.517760]

Now that you have a point and a polygon primitive you can use the primitive helper methods.

// add a new vertex to our polygon
polygon.insertVertex([-122.670851, 45.513189], 2);

// figure out if our point is within our polygon
point.within(polygon); // returns true

You can also have Terraformer perform many geometric operations like convex hulls and bounding boxes.

var convexHull = polygon.convexHull();

point.within(convexHull); // returns true

var boundingBox = polygon.bbox(); // returns the geojson bounding box for this object.


Building the documentation

To build the site locally, first bundle install then bundle exec middleman to run a local server. Maintainers can run bundle exec middleman build, then grunt gh-pages to deploy to github pages.


Find a bug or want to request a new feature? Please let us know by submitting an issue.


Esri welcomes contributions from anyone and everyone. Please see our guidelines for contributing.


A copy of the license is available in the repository's LICENSE file.

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