1. A non-transitory machine readable medium storing a mapping application which when executed by at least one processing unit of an electronic device renders map portions, the mapping application comprising: a map receiver for receiving map tiles from a mapping service in response to a request for the map tiles needed for a particular map view, each map tile comprising vector data describing a map region; a plurality of mesh building modules for using the vector data in at least one map tile to build a plurality of polygonal meshes for a plurality of different constructs in a particular layer of the particular map view, wherein a first built mesh defines roads in the map region and a second built mesh defines non-road constructs in the map region; a mesh aggregation module for combining meshes from several mesh building modules into a renderable tile for the particular map view; and a rendering engine for rendering the particular map view using the renderable tile.