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Generate Mapnik MML & XML for single postgis tables with style persistance.
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Need to simply generate a Mapnik map from a dynamic PostGIS table?

Grainstore is an opinionated Carto MML style store for PostGIS tables, views or sql queries that outputs Mapnik XML stylesheets.

Map styles can be defined in the Carto map styling language or use default styles. The Carto styles are persisted and Mapnik XML output cached in Redis, making it a good choice for use in map tile servers.

The generated Mapnik XML stylesheet plugs directly into Mapnik or Mapnik based tile server to render a map and interactivity layer.

Grainstore is braindead simple:

1 db + 1 table/query + 1 style = 1 Mapnik XML stylesheet.


1 db + N queries + N styles = 1 Mapnik XML stylesheet.

Typical use

For using multiple layers use an array type for the 'sql' parameter and for the 'style' parameter. Each resulting layer will be named 'layerN' with N starting from 0 (needed to properly reference the layers from the 'style' values).


npm install


  • node.js (tested from 0.8.x to 0.10.x)
  • npm

Additional test dependencies

  • libxml2
  • libxml2-devel


var grainstore = require('grainstore');

var params = {
  dbname: 'my_database',
  sql:'select * from my_table',
  style: '#my_table { polygon-fill: #fff; }'

// fully default.
var mmls = new grainstore.MMLStore();
var mmlb = mmls.mml_builder(params);
mmlb.toXML(function(err, data){
    console.log(data); // => Mapnik XML for your database with default styles

// custom pg settings.
var mmls = new GrainStore.MMLStore();

// see mml_store.js for more customisation detail 
var options = {
  Map: {srid: 4326},
  Datasource: {
    user: "postgres",
    geometry_field: "my_geom"

mmlb = mmls.mml_builder(params, options);
mmlb.toXML(function(err, data){
    console.log(data); // => Mapnik XML of custom database with default style

// custom styles.
var mmls = new GrainStore.MMLStore();
var mmlb = mmls.mml_builder(params);
mmlb.toMML(function(err, data){
    console.log(data) // => Carto ready MML

mmlb.toXML(function(err, data){
    console.log(data); // => Mapnik XML of database with custom style

For more examples, see the tests.


To run the tests, from the project root:

npm test


npm publish



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