EMViewshed is an efficient algorithm used to viewshed computation on huge terrains stored in the external memory.
It was developed using C++ programming language and it is able to
process DEMs with more than 6GB. This algorithm also processes part of
the data in the internal memory in order to improve the processing
The data are managed in the external memory with the STXXL library (Standard Template Library for Extra Large Data Sets). More information about this library can be found here.
A viewshed example
This work was partially supported by CNPq - the Brazilian Council of Technological and Scientific Development,
FAPEMIG - the Research Support Foundation of the State of Minas Gerais (Brazil) and by NSF grants CCR-0306502 and DMS-0327634 and by DARPA/DSO/GeoStar.