Triangulated Irregular Networks (TIN)

A triangulated irregular network (TIN) is a data structure for representing 3D surfaces comprised of connected, nonoverlapping triangles. This is one technique used in the GIS field to represent terrain models. In contrast, another common terrain representation is the digital elevation model (DEM), which uses a regular grid of height values. For each height value in a terrain model, a TIN representation stores a full (x, y, z) coordinate, often referred to as a mass point, whereas a DEM representation requires only a single z (elevation) value because the (x, y) coordinates can be implicitly defined due to the regular structure of the grid. Figure 1 illustrates the difference between a TIN and a DEM representation for the same terrain model. (Note that this figure ...