sethvincent / osm-p2p-geojson

Export GeoJSON from osm-p2p-db

osm-p2p-geojson

Transform OSM documents in an osm-p2p-db to GeoJSON

Table of Contents

• Installation
• Usage
• API
• Contribute
• License

Install

npm install osm-p2p-geojson

Usage

// streaming:
var getGeoJSON = require('osm-p2p-geojson')
var stream = getGeoJSON(osm)

var q = osm.query({
  bbox: [-Infinity, -Infinity, Infinity, Infinity]
})

// outputs geojson object
q.pipe(stream).pipe(process.stdout)

// or as callbacks:
osm.query({
  bbox: [-Infinity, -Infinity, Infinity, Infinity]
}, function (err, docs) {
  getGeoJSON(osm, { docs: docs }, function (err, geojson) {
    console.log(geojson)
    // outputs geojson object
  })
})

API

var getGeoJSON = require('osm-p2p-geojson')

var stream = getGeoJSON(osm[, options][, callback])

Creates a TransformStream that will take as input a stream of osm-p2p documents and outputs a stream of GeoJSON. If you prefer a callback rather than a stream for reading output, you can pass callback(err, geojson).

• osm - a osm-p2p-db
• docs - a list of OSM documents. If not provided here, they must be written to the returned stream.
• options.metadata - Array of metadata properties to include as GeoJSON properties. Defaults to ['id', 'version', 'timestamp']
• options.objectMode - when true will return a stream of GeoJSON feature objects instead of stringified JSON. Default false. You can also use getGeoJSON.obj()
• options.map - a function that maps a Feature to another Feature. Defaults to the no-op function mapFn (feature) { return feature }
• options.polygonFeatures - either a list of tag keys and values that are polygons (for schema see https://github.com/tyrasd/osm-polygon-features/blob/master/schema.json) or a function that will be called with two arguments: coordinates (from the GeoJSON geometry) and tags (a hash of tag key-value pairs) and should return true for polygons.

N.B.: If options.objectMode is enabled and no callback is provided, the resultant object stream will emit GeoJSON Feature objects. This is not valid GeoJSON as-is: the recipient of the stream will need to either wrap these Features into a FeatureCollection or otherwise further transform them.

Contribute

PRs accepted.

Small note: If editing the Readme, please conform to the standard-readme specification.

License

MIT © Gregor MacLennan