} else if (layerConfig.type === 'BingAerialWithLabels') {
        if (!_(layerConfig.options).has('bingApiKey')) { throw Error('Bing API key requried!') }
        that.list.push(Bing.doNew('AerialWithLabels', layerConfig.options.bingApiKey).layer)
      } else {
        throw Error("Invalid layer type '" + layerConfig.type + "'")