osmtogeojson

Converts OSM data to GeoJSON. Try the demo!

stable
real OSM polygon detection
proper OSM multipolygon support
full support for extended Overpass API geometry modes
well tested and proven
fast

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

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.

nubiofs/osmtogeojson