Approximations in Trimetric drawings are common. There are, however, actually three types of axonometric projections&colon; "isometric", "dimetric" and "trimetric". The Chamberlin trimetric projection is neither conformal nor equal-area. Sub-types of "axonometric projection" include "isometric", "dimetric" and "trimetric projections". A Chamberlin trimetric map therefore gives an excellent overall sense of the region being mapped. If all forshortenings are different, the projection is called trimetric.