Windshaft map tiler

A Node.js based webmercator map tile server for PostGIS with Carto map styling API.

• Pluggable routing to provide customizable tile API URL endpoints
• Before and after filters to allow custom access control and caching strategies
• Can render all table data, or data restricted by SQL query
• Generates image and UTFGrid interactivity tiles
• Accepts, stores, serves, and applies map styles written in the Carto markup language (same markup as Mapbox Tilemill)
• Accepts custom map styles on a per tile basis in the tile request
• Allows setting of CORS headers to allow access to tile data from Javascript
• No multi layer or composite support yet

![Puma Concolor by @eightysteele] ( http://github.com/Vizzuality/Windshaft/raw/master/examples/puma_concolor.png )

Being a dynamic map renderer, windshaft commits some map server 'sins' in its raw form. The idea is that you the developer will want to graft your own auth/metrics/caching/scaling on top of decent core components. Same old story: high cohesion, low coupling makes us happy.

Windshaft is a library used by cartodb.com, an Open Source Geospatial Database on the Cloud.

Limitations

• supports single layer render only.
• for speed, expects geometry projected to webmercator (EPSG:3857) in a column called the_geom_webmercator.
• Mapnik is a fast moving target. This currently is pinned to the Mapnik 2.0 release.

Dependencies

• Node 0.4.x & npm
• Mapnik 2.0
• PostgreSQL >8.3.x, PostGIS >1.5.x
• Redis >2.2.x

Install

npm install

Usage

var Windshaft = require('windshaft');

// Configure pluggable URLs
// =========================
// The config object must define grainstore config (generally just
// postgres connection details), redis config, a base url and a function
// that adds 'dbname' and 'table' variables onto the Express.js req.params
// object.  In this example, the base URL is such that dbname and table will
// automatically be added to the req.params object by express.js. req2params
// can be extended to allow full control over the specifying of dbname and
// table, and also allows for the req.params object to be extended with
// other variables, such as:
//
// * sql - custom sql query to narrow results shown in map)
// * geom_type - specify the geom type (point|polygon) to get more
//               appropriate default styles
// * cache_buster - forces the creation of a new render object, nullifying
//                  existing metatile caches
// * interactivity - specify the column to use in the UTFGrid
//                   interactivity layer (defaults to null)
// * style - specify map style in the Carto map language on a per tile basis
//
// the base url is also used for persisiting and retrieving map styles via:
//
// GET  base_url + '/style' (returns a map style)
// POST base_url + '/style' (allows specifying of a style in Carto markup
//                           in the 'style' form variable).
//
// beforeTileRender and afterTileRender could be defined if you want yo
// implement your own tile cache policy. See an example below

var config = {
        base_url: '/database/:dbname/table/:table',
        req2params: function(req, callback){callback(null,req)},
        grainstore: {
		datasource: {
			user:'postgres', host: '127.0.0.1',
        		port: 5432
		}}, //see grainstore npm for other options
        redis: {host: '127.0.0.1', port: 6379},
        // this two filters are optional
        beforeTileRender: function(req, res, callback)
	{
            callback(null);
        },
        afterTileRender: function(req, res, tile, headers, callback)
	{
            callback(null, tile, headers);
        }
    };

// Initialize tile server on port 4000
var ws = new Windshaft.Server(config);
ws.listen(4000);
console.log("map tiles are now being served out of: http://localhost:4000"
            + config.base_url + '/:z/:x/:y.*');

// Specify .png, .png8 or .grid.json tiles.

See examples directory for running server and maptile viewer

Installing Mapnik 2.0

Source http://prdownload.berlios.de/mapnik/mapnik-2.0.0.tar.bz2

OSX

http://trac.mapnik.org/wiki/MacInstallation/Homebrew

Linux

There may be ubuntu ppa's out there with stable 2.0 packages right now - but beware, windshaft requires the official 2.0 release, not a nightly or head version.

Tests

Windshaft has a unit and acceptance test suite. To run them, please read ./test/README.md

-- Thanks to the Mapnik and Mapbox team for making such flexible tools