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osmtogeojson

osmtogeojson

Converts OSM data to GeoJSON. Try the demo!

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

Build Status

Usage

command line tool

Installation:

  $ npm install -g osmtogeojson

Usage:

$ osmtogeojson file.osm > file.geojson

Supported command line options are shown with:

$ osmtogeojson --help

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). On a Unix system, you can use the following command:

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

nodejs library

Installation:

$ npm install osmtogeojson

Usage:

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

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 will be a simple key-value list instead of a structured json object (with separate tags and metadata). default: false
    • 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.