1. A computer implemented method for generating a map model, the method comprising: identifying one or more first colors in an image as associated with navigable space in a geographic area; analyzing, using a processor, the image to identify areas of the navigable space by identifying pixels within the image that correspond to the one or more first colors; generating one or more convex polygons that cover the areas of the navigable space; and generating the map model, wherein the map model comprises the one or more convex polygons and a set of adjacency relationships among the one or more convex polygons.