Advanced Spatial Decision Support Systems

Background

The prototype system was capable of modifying terrain data to add data obtained from a GIS system. For example if the land use data indicated that an area of terrain was covered by forest the prototype would add an indication of this to the 3D visuaalisation of the terrain.

As part of this work walkthroughs of areas around the Clwyd forest and mount Snowdon were integrated with web based information that could be accessed from within the virtual environment. For example a user could click on an icon in the virtual world and be presented with a photograph of the real environment from that viewpoint.

Example Images

Below is a contour map with the forest outline drawn on. Several viewpoints are defined on this map, the most interesting one to us is marked with an "S", the summit viewpoint.

Below is a photograph from the summit viewpoint marked above.

Below is the equivalent view generated from the terrain model. Here the vector map of the restocking proposals is draped over.

Visiting the Clwyd Valley in virtual reality is possible using DIVE and a WWW browser.

Using the digitised terrain data, a DTM was created by a module of the GIS system. Firstly, a triangulation surface was produced from the contours and spot heights. From this a height could be derived for each point in a rectangular grid "laid over" the traingulated surface. Below we see the DTM, colour-coded by height, with the vector map of restocking proposals superimposed.

Having produced the DTM, various methods of visual analysis are possible. Slope, aspect or shade maps can be produced, or maps showing the visual impact of certain points on the surrounding terrain. Below is a screenshot of the shaded DTM, here with the light source at the top-right of the screen.

In addition to the 2-Dimensional maps described earlier, 3-Dimensional views can be derived from the DTM. These can either be perspective views from any point within or outside the model, or isometric views from around the model, the latter giving a useful "bird's eye" view of the terrain. Any vector map of the same area can be draped over the DTM, which in this case allowed the relationship bewteen the various forest designs and the terrain to be visualised. Below is an isometric view of the restocking plan.

Links

The following are links to related pages: