GeoJSONタイルのフォーマットの違い（TileLayer.GeoJSON vs Tangram） ref: http://qiita.com/handygeospatial/items/cc0cf63b13e2857c56ee

file0.txt

/**
 Mapzen/OSM.US-style GeoJSON vector tiles
 @class GeoJSONTileSource
*/
export class GeoJSONTileSource extends NetworkTileSource {

    constructor (source) {
        super(source);
        this.type = 'GeoJSONTileSource';
    }

    parseTile (tile, response) {
        tile.layers = JSON.parse(response);

        TileSource.projectTile(tile); // mercator projection
        TileSource.scaleTile(tile); // re-scale from meters to local tile coords
    }
}

file1.txt

{
   "earth": {
      "type":"FeatureCollection",
      "features": [...],
      ...
   },
   "landuse": {
      "type":"FeatureCollection",
      "features": [...],
      ...
   }
}