Software, at a networked central computer or at a wireless mobile user device, uses GPS coordinates of a mobile user device's current location to determine a polygon in which the GPS coordinates lie. Upon determining the polygon that surrounds the current location, the software can perform a task related to the polygon. Examples of tasks include: determining traffic camera images to display on the mobile user device based on the location, speed, and heading of the user device. The images can include advertisements that pertain to the general vicinity, or demographics of those typically in the vicinity, of the cameras' coverage area. Another task includes associating performance data from a vehicle, and stored in a table, for a given location with a corresponding polygon that surrounds the location; processing the data; and assigning a risk value to the polygon based on the corresponding performance data.