Special Topics in GIS, Module 2.1

In this week's lab assignment, we explored TIN (triangulated irregular network) datasets containing terrain data. Unlike typical raster DEMs, TINs consist of a patchwork of triangles using the input sample points as vertices. Thus, they retain the exact input values at the vertices, which is not always the case with interpolated raster DEMs. That means they can easily accommodate an adaptive sampling strategy in variable terrain. Although TINs are more complex than raster DEMs, they can also be better for some applications because of that added precision. However, their angularity means they do not always capture detailed features accurately, as illustrated by the screenshots below of a TIN from Bear Lake, CA. The outline of the lake was not clear in the original TIN, and had to be incorporated by using a shapefile of the lake to create a hard edge in the TIN surface at the correct elevation.