Default value: 'bingMapsRoadSource'
The source of the wijmaps tile layer. Wijmaps provides some built in sources: <ul> <li>bingMapsRoadSource</li> <li>bingMapsAerialSource</li> <li>bingMapsHybridSource</li> </ul> Set to null if want to hide the tile layer.<br> Set to a IMultiScaleTileSource object if want to use another map tile server.