scene.yaml

cameras:
    camera1:
        type: perspective
        focal_length: [[16, 2], [20, 6]] # pairs of [zoom, focal len]
        vanishing_point: [-250, -250] # relative to center of screen, in pixels

lights:
    light1:
        type: directional
        direction: [0, 1, -.5]
        diffuse: .3
        ambient: 1

sources:
    mapzen:
        type: TopoJSON
        url: https://tile.mapzen.com/mapzen/vector/v1/all/{z}/{x}/{y}.topojson
        url_params:
            api_key: mapzen-rtjEFK2
        max_zoom: 16

layers:
    earth:
        data:
            source: mapzen
            layer: earth
        draw:
            polygons:
                order: function() { return feature.sort_rank; }
                color: '#ddeeee'
    landuse:
        data:
            source: mapzen
            layer: landuse
        draw:
            polygons:
                order: function() { return feature.sort_rank; }
                color: '#aaffaa'
                interactive: true

    water:
        data:
            source: mapzen
            layer: water
        draw:
            polygons:
                order: function() { return feature.sort_rank; }
                color: '#88bbee'

    roads:
        data:
            source: mapzen
            layer: roads
        filter:
            not: {kind: [ferry, rail, path]}
        draw:
            lines:
                order: function() { return feature.sort_rank; }
                color: gray    
                width: 8
        highway:
            filter:
                kind: highway
            draw:
                lines:
                    color: '#cc6666'
                    width: 12
                    outline:
                        color: grey
                        width: 3
        minor_road:
            filter:
                kind: minor_road
            draw:
                lines:
                    color: lightgrey
                    width: 5    
    buildings:
        data:
            source: mapzen
            layer: buildings
        draw:
            polygons:
                order: function() { return feature.sort_rank; }
                color: |
                    function () {
                        var h = feature.height || 20;
                        h = Math.min((h + 50)/ 250, .8);
                        h = Math.max(h, .4);
                        return [h, h, h];
                    }
                extrude: true