A modular, open-source search engine for our world.

Pelias is a geocoder powered completely by open data, available freely to everyone.

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What is Pelias?

Pelias is a search engine for places worldwide, powered by open data. It turns addresses and place names into geographic coordinates, and turns geographic coordinates into places and addresses. With Pelias, you're able to turn your users' place searches into actionable geodata and transform your geodata into real places.

We think open data, open source, and open strategy win over proprietary solutions at any part of the stack and we want to ensure the services we offer are in line with that vision. We believe that an open geocoder improves over the long-term only if the community can incorporate truly representative local knowledge.

polygon-lookup

A data-structure for performing fast, accurate point-in-polygon intersections against (potentially very large) sets of polygons. PolygonLookup builds an R-tree, or bounding-box spatial index, for its polygons and uses it to quickly narrow down the set of candidate polygons for any given point. If there are any ambiguities, it'll perform point-in-polygon intersections to identify the one that really intersects. PolygonLookup operates entirely in memory, and works best for polygons with little overlap.

API

PolygonLookup(featureCollection)

• featureCollection (optional): A GeoJSON collection to optionally immediately load with .loadFeatureCollection().

PolygonLookup.search(x, y, limit)

Narrows down the candidate polygons by bounding-box, and then performs point-in-polygon intersections to identify the first n container polygon (with n = limit, even if more polygons really do intersect).

• x: the x-coordinate to search for
• y: the y-coordinate to search for
• limit optional: the upper bound for number of intersecting polygon found (default value is 1, -1 to return all intersecting polygons)
• return: the intersecting polygon if one was found; a GeoJson FeatureCollection if multiple polygons were found and limit > 1; otherwise, undefined.

PolygonLookup.loadFeatureCollection(featureCollection)

Stores a feature collection in this PolygonLookup, and builds a spatial index for it. The polygons and rtree can be accessed via the .polygons and .rtree properties.

• featureCollection (optional): A GeoJSON collection containing some Polygons/MultiPolygons. Note that MultiPolygons will get expanded into multiple polygons.

example usage

var PolygonLookup = require( 'polygon-lookup' );
var featureCollection = {
	type: 'FeatureCollection',
	features: [{
		type: 'Feature',
		properties: { id: 'bar' },
		geometry: {
			type: 'Polygon',
			coordinates: [ [ [ 0, 1 ], [ 2, 1 ], [ 3, 4 ], [ 1, 5 ] ] ]
		}
	}]
};
var lookup = new PolygonLookup( featureCollection );
var poly = lookup.search( 1, 2 );
console.log( poly.properties.id ); // bar