1. A method comprising: providing a user interface that displays a map with a user-operable element that is superimposed on the map and has a shape defined by boundaries of the user-operable element; receiving user input that indicates that a region of the map is selected, the region being defined by the shape and the boundaries of the user-operable element superimposed on the map; and causing the user interface to display location markers within the selected region defined by the shape and the boundaries of the user-operable element superimposed on the map in response to the user input that indicates that the region of the map is selected, the causing of the user interface to display the location markers being performed by a processor of a machine.