Terrain height and ground cover computer data: an overview

Terrain data used for field strength prediction began in earnest when curves agreed for international negotiations became those of CCIR Recommendation 370. These curves required the collection of two parameters: HAMT-height of the transmitting antenna above the average ground level between 3 and 15 km from the transmitter toward the receiver; and Δh-difference between heights exceeded by 10% and 90% of the terrain in the range 10 to 50 km from the transmitter. The author discusses the history of collecting this data, the data format, means of collecting the data including aerial photography and satellite remote sensing, ground profile production, prediction algorithms, and the system used by Vodafone