README.md

Leaflet.VectorTiles

Render (GeoJSON) vector tiles on an L.GridLayer with an L.Canvas renderer

This extension also includes L.FontCanvas which extends L.Canvas with the capability of rendering fonts (useful for icon fonts).

API documentation is in API.md.

Dependencies

• Leaflet 1.0.3 (note that it will work in Leaflet 1.0.0 but performance if very bad)

Usage

Include the following in your HTML header:

<link rel="stylesheet" href="leaflet.css"/>
<script src="leaflet-src.js"></script>
<script src="Leaflet.VectorTiles.js"></script>

Note: Leaflet.VectorTiles.js must come after Leaflet

Example:

var map = L.map('map', {
  renderer: new L.FontCanvas()
});

var url = 'http://mytiles.party/{z}/{x}/{y}';

var vtLayer = new L.VectorTiles(url, {
  getFeatureId: function(feature) {
    return feature.properties.id;
  },
  debug: true, // to show tile boundaries
  style: {
    treeType: {
      oak: {
        color: 'green',
        font: '10px icomoon',
        content: '\ue91a'
      },
      pine: {
        color: 'red'
      }
    },
    building: {
      guggenheim: {
        color: 'purple',
        font: '20px icomoon',
        content: '\ue915' // house icon
      }
    }
  }
});

vtLayer.addTo(map);

All styling is by feature properties. The keys in the style option are property names and the keys in those objects correspond to values.

Developing

npm run build

The above outputs a bundle named leaflet.vector-tiles.js

npm run build-dev

Outputs the bundle with a source map for easier debugging

To run the example app, start the development server:

npm start

Now do:

cd example
npm install
npm start

and then point your browser to http://localhost:12345

Tiles

As is, for each tile, the library expects the tile server to respond with an array like:

[
  {
    layer: <string>, // layer name
    features: <GeoJSON FeatureCollection> // features in this layer
  },
  ...
]

Quirks

Performance

Performance is in very bad in Leaflet 1.0.0. It is much better in Leaflet 1.0.3.

Panning

tileunload doesn't fire on pan so old tiles stick around as you pan around.

Leaflet.FontCanvas

The FontCanvas class acutally doesn't have anything to do with this library. It should be removed and implemented as a separate extension.

TODO

• Styling by layer

• On zoom and pan every tile is reloaded and rerendered even though tiles almost never change. Figure out how to reuse tiles across zoom levels.