Estimating radio frequency (RF) power in a geographic area is almost as old as wireless technology itself. It is crucial to anyone who is working or doing business with wireless technologies: wireless operators, the military, regulators, etc. Under a cognitive radio paradigm, spectrum usage is no longer static and is migrating towards dynamic and shared access paradigms. Enabling this evolution requires the estimation of the Radio Frequency map (RF map) of a given area. A variety of methods have already been proposed and tested to accomplish this estimation by leveraging decades of work on spatial interpolation methods. In this work, we justify, through analysis and simulation, using the Discrete Cosine Transform (DCT) as a more dynamic and accurate interpolation technique through comparison to other deterministic methods such as the Inverse Distance Weighting (IDW) method.