togpx v0.5.4

togpx

Converts GeoJSON to GPX.

Usage

• as a command line tool:

    $ npm install -g togpx
    $ togpx file.geojson > file.gpx

• as a nodejs library:

    $ npm install togpx
  
    var togpx = require('togpx');
    togpx(geojson_data);

• as a browser library:

    <script src='togpx.js'></script>
  
    togpx(geojson_data);

API

togpx( geojson, options )

• geojson: the GeoJSON data.
• options: optional. The following options can be used:
  • creator: Specify a creator string that is used to specify the software that created the final GPX file. Default is togpx.
  • metadata: An object containing metadata about the to be converted dataset. Will be included in the GPX in the <metadata> tag. Usefull for providing information like copyright, time, desc, etc.
  • featureTitle: Defines a callback that is used to construct a title (<name>) for a given GeoJSON feature. The callback is called with the GeoJSON feature's properties object.
  • featureDescription: Defines a callback that is used to construct a description (<desc>) for a given GeoJSON feature. The callback is called with the GeoJSON feature's properties object.
  • featureLink: Defines a callback that is used to construct an URL (<link>) for a given GeoJSON feature. The callback is called with the GeoJSON feature's properties object.
  • featureCoordTimes: Defines a callback that is called for each feature to determine timestamps of each coordinate. Gets called with the current feature as a parameter, must return an array of UTC ISO 8601 timestamp strings for each coordinate of the feature. Alternatively. this option can be a string, in which case the corresponding feature property is used to read the times array.

The result is a string of GPX XML.

GPX

The conversion from GeoJSON to GPX is (by definition) lossy, because not every GeoJSON feature can be represented with the simple data types present in GPX files and GPX does not support arbitrary feature properties. This library tries to convert as much geometry and information as possible:

• Points are converted to Waypoints.
• Lines are converted to Tracks.
• (Multi)Polygons are represented as a Track of their outline(s).
• By default, the name tag of GPX elements will be determined by a simple heuristic that searches for the following GeoJSON properties to construct a meaningful title: name, ref, id
• By default, the desc tag of GPX elements will be constructed by concatenating all respective GeoJSON properties.
• Elevation is included in the output if the GeoJSON coordinates contain altitude as a third value ([lon, lat, altitude])
• Timestamps are included in the GPX output if the GeoJSON has a times or coordTimes property that is an array of UTC ISO 8601 timestamp strings. See the featureCoordTimes option for customizing this behaviour.