-VikMapSource is the "interface", the really base class of the MapSource tree.
-In order to implement a MapSource, you have to prefer to derive from VikMapSourceDefault, a less abstract class, adding a property based implementation for some aspects of the VikMapSource interface.
-Then, you have to provide implementation for coord_to_mapcoord, mapcoord_to_center_coord and download methods.
+VikMapSource is the "interface", the really base class of the
+MapSource tree. In order to implement a MapSource, you have to prefer
+to derive from VikMapSourceDefault, a less abstract class, adding a
+property based implementation for some aspects of the VikMapSource
+interface. Then, you have to provide implementation for
+coord_to_mapcoord, mapcoord_to_center_coord and download methods.