The map draping perfected in the VB6 environment was OK but it wasn't quite what I was after. What had inspired me was how I might make a pseudo-realistic view of the landscape.
I realised if I could edge-match the data on the map rasters I could plot the building and road, and forest areas. This took a long while to work out since the rasters are anti-aliased for printing which isn't where you'd want to start for edge matching.
Eventually I worked out a palette based pixel examination system which would parse the map rasters and attempt to edge map them. This took several months as I had to research and understand the basic mathematics behind polygon-line intersects and concave hull generation.
The problem is that this processing is second-hand - the Ordnance Survey already have all this polygonal information and charge a hefty sum to release it. Looking at the results I got it was clear I was not progressing in the right direction. Not only were my textures awful (a sixth former could do better) but I hadn't really grasped that was was needed was the feel of the landscape.
I hit upon a few art websites which algorithmically generate fake landscapes - the key was to make it such that it used understandable graphical metaphors. Here I generated a cloud system and grass textures as well as trees. The trees used a technique called Signposting which required the 2d bitmap of the trees to be oriented side on to the viewer as they move through the landscape. Tricky, and it sounds very processor intensive, but with only a few Km to play with there was no slowdown.
Eventually I realised my edge-matching had come to its logical conclusion. What I needed was real data, and lots of it. I set myself a goal of being able to see right across the UK seamlessly and at high rendering speed.
This was an epic computational challenge. The problem with landscapes, which I had not grasped in the slightest, is that the amount of information within the follows an square rule. The further away you can see, the exponentially more data and more processing is required.
... I always wondered why 3d games were set in corridors. Now I knew.