/osmtogeojson

convert osm to geojson

Primary LanguageJavaScriptMIT LicenseMIT

osmtogeojson

Converts OSM data to GeoJSON. Try the demo!

This code is used in and maintained by the overpass turbo project.

Build Status

Usage

  • as a command line tool:

      $ npm install -g osmtogeojson
  $ osmtogeojson file.osm > file.geojson

    When working with extra large data files (≳ 100 MB) it is recommended to run the programm with a little extra memory to avoid process out of memory errors. The easiest way to do this is by running the command as node <path-to-osmtogeojson> and setting the --max_old_space_size=… parameter to the available memory size in MB (osmtogeojson typically needs about 4-5 times the input data size):

      $ node --max_old_space_size=8192 `which osmtogeojson` large.osm > large.geojson

  • as a nodejs library:

      $ npm install osmtogeojson

  var osmtogeojson = require('osmtogeojson');
  osmtogeojson(osm_data);

  • as a browser library:

      <script src='osmtogeojson.js'></script>

  osmtogeojson(osm_data);

API

osmtogeojson( data, options )

Converts OSM data into GeoJSON.

  • data: the OSM data. Either as a XML DOM or in OSM JSON.
  • options: optional. The following options can be used:
    • flatProperties: If true, the resulting GeoJSON feature's properties won't be a structured json object rather than a simple key-value list.
    • uninterestingTags: Either a blacklist of tag keys or a callback function. Will be used to decide if a feature is interesting enough for its own GeoJSON feature.
    • polygonFeatures: Either a json object or callback function that is used to determine if a closed way should be treated as a Polygon or LineString. read more

The result is a javascript object of GeoJSON data:

GeoJSON

The GeoJSON produced by this library will include exactly one GeoJSON-feature for each of the following OSM objects (that is everything that is also visible in overpass turbo's map view):

  • all unconnected or interesting tagged nodes (POIs)
  • all ways (except uninteresting multipolygon outlines)
  • all multipolygons (simple multipolygons with exactly one closed outer way are present via their outer way)

All data is given as a FeatureCollection. Each Feature in the collection has an id property that is formed from the type and id of the original OSM object (e.g. node/123) and has the member properties containing the following data:

  • type: the OSM data type
  • id: the OSM id
  • tags: a collection of all tags
  • meta: metainformaton about the feature (e.g. version, timestamp, user, etc.)
  • relations: an array of relations the feature is member of. Each relation is encoded as an object literal containing the following properties: role (membership role), rel (the relation's id) and reltags (contains all tags of the relation)
  • tainted: this flag is set when the feature's geometry is incomplete (e.g. missing nodes of a way or missing ways of a multipolygon)

If the option flatProperties is set to true, the properties object will not contain any nested object literals, but directly provide a concise id, meta data and the tags of the respective OSM object.