@tmcw/togeojson

Convert KML, GPX, and TCX to GeoJSON.

togeojson development is supported by 🌎 placemark.io

This converts KML, TCX, & GPX to GeoJSON, in a browser or with Node.js.

• Dependency-free
• Tiny
• Tested
• Node.js + Browsers

📕 API Documentation

This is a JavaScript library that lets projects convert KML and GPX to GeoJSON. If you're looking for a command line too, use @tmcw/togeojson-cli. If you want to convert one KML or GPX file, use my online tool. If you want to convert another format, consider GDAL.

Property conversions

In addition to converting KML’s <ExtendedData> verbatim, @tmcw/togeojson also encodes parts of KML, GPX, and TCX files that otherwise would be lost.

KML

• Style properties: fill-color, fill-opacity, stroke, stroke-opacity, icon-color, icon-opacity, label-color, label-opacity, icon-scale, icon-heading, icon-offset, icon-offset-units

GPX

• Style properties: stroke, stroke-opacity, stroke-width

TCX

• Line properties: totalTimeSeconds, distanceMeters, maxSpeed, avgHeartRate, maxHeartRate, avgSpeed, avgWatts, maxWatts

This also emits the geojson-coordinate-properties format to include time and other attributes that apply to each coordinate of a LineString.

Ground overlays

Example of working with Ground Overlays in Mapbox GL JS

KML GroundOverlays are now supported, and transformed into Features with Polygon geometries. They have two defined properties:

{
  "@geometry-type": "groundoverlay",
  "icon": "https://url.to.image…"
}

Both gx:LatLonQuad and LatLonBox-based ground overlays are supported.

CLI

Use @tmcw/togeojson-cli to use this software as a command-line tool.

Node.js

Install it into your project with npm install --save @tmcw/togeojson.

// using togeojson in nodejs

const tj = require("@tmcw/togeojson");
const fs = require("fs");
// node doesn't have xml parsing or a dom. use xmldom
const DOMParser = require("xmldom").DOMParser;

const kml = new DOMParser().parseFromString(fs.readFileSync("foo.kml", "utf8"));

const converted = tj.kml(kml);

ES Modules

// The ES Module provides named exports, to import kml, gpx,
// and other parts of the module by name.
import { kml } from "@tmcw/togeojson";

Browser

<script type="module">
  import { kml } from "https://unpkg.com/@tmcw/togeojson?module";

  fetch("test/data/linestring.kml")
    .then(function (response) {
      return response.text();
    })
    .then(function (xml) {
      console.log(kml(new DOMParser().parseFromString(xml, "text/xml")));
    });
</script>

KML Feature Support

• Point
• Polygon
• LineString
• name & description
• ExtendedData
• SimpleData
• MultiGeometry -> GeometryCollection
• Styles
• Tracks & MultiTracks with gx:coords, including altitude
• TimeSpan
• TimeStamp
• Folders (with kmlWithFolders)
• GroundOverlays
• NetworkLinks

GPX Feature Support

• Line Paths
• Line styles
• Properties
  • 'name', 'cmt', 'desc', 'link', 'time', 'keywords', 'sym', 'type' tags
  • gpxx Garmin extensions on tracks and routes
  • 'author', 'copyright' tags

FAQ

How does this differ from mapbox/togeojson?

• This repository is maintained.
• It’s available as an ES Module. If you're using a modern JavaScript bundler or using ES Modules in the browser, this makes it a bit more efficient and sometimes easier to use.
• Conversion methods are available as generators, which makes the conversion of big files more efficient.
• The command line utility was moved to tmcw/togeojson-cli, which lets this module enjoy reduced dependencies: installing @tmcw/togeojson doesn’t require any other dependencies.

Why doesn't toGeoJSON support NetworkLinks?

The NetworkLink KML construct allows KML files to refer to other online or local KML files for their content. It's often used to let people pass around files but keep the actual content on servers.

In order to support NetworkLinks, toGeoJSON would need to be asynchronous and perform network requests. These changes would make it more complex and less reliable in order to hit a limited usecase - we'd rather keep it simple and not require users to think about network connectivity and bandwith in order to convert files.

NetworkLink support could be implemented in a separate library as a pre-processing step if desired.

Should toGeoJSON support feature X from KML?

This module should support converting all KML and GPX features that have commonplace equivalents in GeoJSON.

Protips:

Have a string of XML and need an XML DOM? There are two main options:

• Use xmldom, a JavaScript module that contains its own XML parser
• Use DOMParser, the native platform XML parser

We recommend that you use xmldom, not the platform. DOMParser requires XML to be valid, which means that any XML namespaces that a KML, GPX, or TCX file contains are valid. A lot of existing data is invalid XML, and will be parsed only in part by DOMParser, but can be fully parsed by xmldom.

Using xmldom (recommended):

const xmldom = require("@xmldom/xmldom");
const dom = new xmldom.DOMParser().parseFromString(xmlStr, "text/xml");

Using DOMParser:

var dom = new DOMParser().parseFromString(xmlStr, "text/xml");

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