Wireless InSite is an RF planning tool for predicting the effects of buildings and terrain on the propagation of electromagnetic waves. It major application is site-specific radio signal propagation prediction including effects of the locations of transmitters and receivers within an urban area. Physical characteristics of rough terrain and urban structures are modeled, electromagnetic calculations are performed, and signal propagation characteristics are evaluated. In addition to the basic ray-tracing capability, Wireless InSite can utilize the optional Moving Window and Urban Canyon FDTD propagation models. Distinct from the ray-based methods, these models simulate propagation by directly solving Maxwell's equations using the Finite-Difference Time-Domain (FDTD) method. Moving Window FDTD is used to simulate propagation of radio waves at UHF and VHF frequencies over irregular terrain. Urban Canyon is intended for high-rise urban environments where the transmitting and receiving antennas are located close to the ground relative to building heights. Wireless InSite's innovative methods provide a powerful new tool in the hands of communication system design engineers.