1. An apparatus for map zooming, comprising instructions stored in a memory that when executed by a processor render a zoom bar, comprising: a plurality of map scale hash marks arranged along an axis of the zoom bar and indicative of a map scale range of a geographic map, the plurality of map scale hash marks comprising: a first map scale hash mark representative of a first map scale; a second map scale hash mark offset along the zoom bar axis from the first map scale hash mark and representative of a second map scale; and a map transformation hash mark located between the first and second map scale hash marks and representative of a transformation of the geographic map from a first map data set defined with reference to the first map scale to a second map data set defined with reference to the second map scale; and a map zoom bar indicator located relative to the first and second map scale hash marks and corresponding to a current map display scale and a zoom level of the geographic map.