Telcik, T.M. (1992) Vehicle navigation using a triangulated irregular 
        network: solving the cross-country problem. Honours Dissertation,
        Department of GIS, School of Computing, Curtin University of
        Technology: Perth (Western Australia).


ABSTRACT

     Finding the shortest path between two locations based
on some constraint is an important vehicle navigation
problem which is receiving renewed interest. Current
Geographic Information Systems (GIS) offer on-road vehicle
navigation in the form of routing along pre-defined road
networks. However, many real-life problems require finding
a shortest path (constrained by some factor) between two
locations using an optimal combination of on-road and off-
road access; this is the Cross-Country Problem (CCP). Such
path-planning may be achieved using weighted polygonal
regions that are assigned a weight proportional to the cost
of traversing them. The problem then becomes one of
minimising travel cost (eg. time).

     A solution to the CCP is presented using an efficient
Digital Terrain Model (DTM) called a Triangulated Irregular
Network (TIN). Triangles and edges in the TIN are assigned
a weight proportional to the cost of traversing them;
triangles represent terrain shape while edges may be
aligned with roads. The TIN Cross-Country Problem solution
is in its early stages: it requires full implementation and
field tests, but it appears a promising approach for real-
world GIS problems of resource allocation and strategic
planning.