Visualisation from digital map databases using transputers

An ever increasing amount of map data for the world´s land masses is held in digital format. The computational demands of producing images in an acceptable time can be met by using high performance and low cost parallel processing machines so that new algorithms can be rapidly prototyped and tested. Such an approach has been made feasible by the use of transputer systems. There are a number of conventional algorithms which take digital surface data and process it to produce the required images. Most current algorithms are inherently sequential and do not, in general, map easily onto parallel processor architectures. The authors show that by careful algorithm design the problem can be mapped onto a number of processors by exploiting the fact that a calculation for one area is not dependent on any other data manipulations other than its own and hence can proceed independently. The algorithm is based on ray casting