ms-webdev/leaflet-pip

point in polygon intersections for leaflet

point in polygon for Leaflet

A Leaflet-friendly API for point in polygon operations, using substack's point in polygon library.

install

With browserify

npm install @mapbox/leaflet-pip

Resolve for a CDN/packaged version:

https://unpkg.com/@mapbox/leaflet-pip@latest/leaflet-pip.js

example

var gjLayer = L.geoJson(statesData);
var results = leafletPip.pointInLayer([-88, 38], gjLayer);
// results is an array of L.Polygon objects containing that point

api

leafletPip.pointInLayer(point, layer L.GeoJSON, [first])

Point can be:

• A two-element array of [lng, lat]
• A L.LatLng object

Layer must be:

• A L.geoJSON layer

first can be:

• boolean: true to accept the first match, or false to return all polygons containing this point. This can be useful if you know that your polygons are non-overlapping or don't care about more than one result, since it will be much faster. By default, this is false and all matches are returned.

Returns:

An array of polygons in which the given point resides, an empty array if there are none. The polygons are returned as direct sublayers, so they can include MultiPolygons. You can call pointInLayer again on those if you want the sub-polygon result.

leafletPip.bassackwards

Leaflet treats literate coordinate arrays as [lat, lon], unlike GeoJSON and any true scotsman. leaflet-pip treats literate coordinate arrays as [lon, lat], but if you set bassackwards to true, it'll do things the Leaflet/Google Maps API way.