map.c

#include <mapnik/map.hpp>
#include <mapnik/load_map.hpp>
#include <mapnik/agg_renderer.hpp>
#include <mapnik/image.hpp>
#include <mapnik/image_util.hpp>

main() {
    mapnik::Map m(256,256);
    mapnik::load_map(m, ‘path/to/file.xml’);
    m.zoom_all();
    mapnik::image_rgba8 im(256,256);
    mapnik::agg_renderer<mapnik::image_rgba8> ren(m, im);
    ren.apply();
    mapnik::save_to_file(im, ‘the_image.png’);
}

map.js

var mapnik = require('mapnik');
var fs = require('fs');

// register fonts and datasource plugins
mapnik.register_default_fonts();
mapnik.register_default_input_plugins();

var map = new mapnik.Map(256, 256);
map.load('./test/stylesheet.xml', function(err,map) {
    if (err) throw err;
    map.zoomAll();
    var im = new mapnik.Image(256, 256);
    map.render(im, function(err,im) {
      im.encode('png', function(err,buffer) {
          fs.writeFile('map.png',buffer, function(err) {
              console.log('saved map image to map.png');
          });
      });
    });
});

map.py

import mapnik

m = mapnik.Map(600,300)
m.background = mapnik.Color('steelblue')
s = mapnik.Style()
r = mapnik.Rule()
polygon_symbolizer = mapnik.PolygonSymbolizer(mapnik.Color('#f2eff9'))
r.symbols.append(polygon_symbolizer)
line_symbolizer = mapnik.LineSymbolizer(mapnik.Color('rgb(50%,50%,50%)'),0.1)
r.symbols.append(line_symbolizer)
s.rules.append(r)
m.append_style('My Style',s)
ds = mapnik.Shapefile(file='ne_110m_admin_0_countries.shp')
layer = mapnik.Layer('world')
layer.datasource = ds
layer.styles.append('My Style')
m.layers.append(layer)
m.zoom_all()
mapnik.render_to_file(m,'world.png', 'png')