GIS4930 - Module 2.1 - TINs and DEMs

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In this lab, we explored Triangulated Irregular Networks (TINs) and Digital Elevation Models (DEMs) to understand how each can represent terrain and how they might be used for analysis.

We started by draping a satellite radar image of Death Valley over a TIN surface, then used a vertical exaggeration to highlight subtle terrain features. This made it easier to see the relationship between jagged land and elevation patterns.

Then we were tasked to build a ski run suitability model using a DEM with three types of rasters: elevation, slope, and aspect. Each factor was reclassified based on ideal ski conditions and then I used the weighted overlay specifically to combine the three reclassified rasters into a final suitability map as well as give weight to each type (25% aspect, 40% elevation, 35% slope), with the most suitable ski run areas appeared being along the upper mountain slopes.

In the third part, I explored TIN symbology by experimenting with slope, aspect, contours, and triangle edges, which would help in the last part where we had to compare TIN contours generated from a DEM Spline.The DEM contours were smoother and more generalized, while the TIN contours followed sharp changes between individual triangles as per the image below.

Some of the greatest differences were that the DEM contours are smoother while the TIN contours are more jagged since they follow the exact triangle boundaries. However, in rolling terrain or areas of small changes, both methods had similar results. The DEM contours seemed more accurate though since they provide continuous elevation representation at a smoother interpolation.

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