cartodb / tilelive-mapnik

mapnik renderer backend for tilelive

tilelive-mapnik

Renderer backend for tilelive.js that uses node-mapnik to render tiles and grids from a Mapnik XML file. tilelive-mapnik implements the Tilesource API.

Installation

yarn install tilelive-mapnik

Though tilelive is not a dependency of tilelive-mapnik you will want to install it to actually make use of tilelive-mapnik through a reasonable API.

Usage

var tilelive = require('tilelive');
require('tilelive-mapnik').registerProtocols(tilelive);

tilelive.load('mapnik:///path/to/file.xml', function(err, source) {
    if (err) throw err;

    // Interface is in XYZ/Google coordinates.
    // Use `y = (1 << z) - 1 - y` to flip TMS coordinates.
    source.getTile(0, 0, 0, function(err, tile, headers) {
        // `err` is an error object when generation failed, otherwise null.
        // `tile` contains the compressed image file as a Buffer
        // `headers` is a hash with HTTP headers for the image.
    });

    // The `.getGrid` is implemented accordingly.
});

Note that grid generation will only work when there's metadata inside a <Parameters> object in the Mapnik XML.

The key fields are interactivity_layer and interactivity_fields. See an example in the tests. These Parameters are normally added by the application that creates the XML, in this case CartoCSS