docs: function readMultiPolygonGeometry(object, arcs) {
    const coordinates = [];
    for (let i = 0, ii = object['arcs'].length; i < ii; ++i) {
      // for each polygon
      const polyArray = object['arcs'][i];
      const ringCoords = [];
      for (let j = 0, jj = polyArray.length; j < jj; ++j) {
        // for each ring
        ringCoords[j] = concatenateArcs(polyArray[j], arcs);
      }
      coordinates[i] = ringCoords;
    }
    return new MultiPolygon(coordinates);
  }