1. A method, comprising: dividing, with a processor, an image of a geographic area of interest into geographical zones, the geographical zones being representative of different physical geographical areas; modifying, with the processor, boundaries of a first one of the geographical zones to more closely conform to an observable landmark or a geographical location observable by a person located in the first one of the geographical zones; storing descriptions for the geographical zones in a computer memory based on the modified boundaries of the first one of the geographical zones; and storing a value representative of a geographical feature represented in the image for the first one of the geographical zones.