When simplifying and approximating surfaces with triangulations, we must determine what is a good triangulation. Thus, we need to define the criterion to measure the quality of a triangulation. There exist many useful criteria in the literature, such as Max-Min angle, Min-Max angle, least squares fit, Gaussian curvature, mean curvature criteria and so on. We introduce two further triangulations based on a minimum area criterion. This thesis compares these different criteria for terrain simplification for a variety of types of terrains.