osm2geojsonstream

Streams OSM data in XML format to GeoJSON. Generates GeoJSON features from OSM ways and nodes.

This is a fork from Ryan Clark's osm2geojson library, forked before osm2geojson incorporated osmium.

Install it globally

npm install -g osm2geojsonstream

Use it from the command line like this

osm2geojsonstream -b "[-111.01032257080078,31.314701127170984,-110.68004608154295,31.447492524518246]"

That will download data from the specified area. Make sure it is not more than 0.25 sq.deg. If you have an extracted XML file, you can...

osm2geojsonstream -f /path/to/osm.xml

You may want to redirect the results to a file unless you can read really fast...

osm2geojsonstream -f /path/to/osm.xml > osm.geojson

Use it in another project like this

npm install osm2geojsonstream

... then in your own scripts:

osm2geojsonstream = require("osm2geojsonstream")();
aReadableStream.pipe(osm2geojsonstream).pipe(aWritableStream);

Optional filtering and mapping

The function returned by require('osm2geojsonstream') can take two optional arguments -- a filter function and a mapping function.

A "filter function" should return true for the features you care about, and false for those you don't. Those that return false will not be included in the final GeoJSON FeatureCollection.

For example:

osm2geojsonstream = require("osm2geojsonstream")(function (feature) {
    return feature.geometry.type === 'Polygon';
});

This will provide an output stream of features that only contains polygons.

The second argument you can provide is a "mapping function". This function accepts one GeoJSON feature, and returns a "transformed" version of the feature. You can use this to adjust the features however you wish. For example:

osm2geojsonstream = require("osm2geojsonstream")(null, function (feature) {
    return {
        type: "Feature",
        properties: {
            name: feature.properties.name.toLowerCase() || 'default name',
            transformedWith: 'osm2geojsonstream',
            originalProperties: feature.properties
        },
        geometry: feature.geometry    
    };
});