code: function () {
      if(this._heading === undefined) {
        return this._createNoHeadingSymbolPathString();
      }
      else {
        if(this._gpsRefPos === undefined || this._map.getZoom() <= this._minSilouetteZoom ) {
          return this._createWithHeadingSymbolPathString();
        }
        else {
          return this._createSilouetteSymbolPathString();
        }
      }
    }
docs: Generates the symbol as SVG path string.
  depending on zoomlevel or track heading different symbol types are generated.
  @return {String} The symbol path string.