Add Overlays to your maps
Map overlays generally refer to the content overlaid or covered on the map, such as labels, vector elements (like lines, polygons, circles, oval, etc.), the information window, etc.. They will be fixed to a certain location in the map, following the map to zoom and move, but not scale accordingly.
The most common map coverage element is Marker, which is the point marker on the map. It usually has default icon and style, or we can customize the icon. Besides Marker, the information window and vector features are also commonly used. We will learn how to use them in this chapter.