code: function (data, noRoam, out) {
          var transform = noRoam ? this._rawTransform : this.transform;
          out = out || [];
          return transform
              ? v2ApplyTransform(out, data, transform)
              : vector.copy(out, data);
      }
docs: Convert a single (lon, lat) data item to (x, y) point.
  @param {Array.<number>} data
  @param {boolean} noRoam
  @param {Array.<number>} [out]
  @return {Array.<number>}