Evaluating the quality of ARC/INFO TINS derived from USGS DEMS

There are a different forms of digital terrain models used to represent topography. The conversion of one model into another is often desirable and appropriate. However, the conversion process may affect the quality of the data in its newer format and thus the ability to represent topography. In this paper a methodology is developed to assess the effects of the transformation of gridded elevation data into triangulated irregular networks. In particular, the quality of Arc/Info based triangulated irregular networks derived from USGS gridded digital elevation models is discussed. Quality is based on comparing a number of descriptive geomorphometric parameters between the original gridded models and the resulting triangulated surfaces created at different levels of generalization. Findings suggest that to maintain reliable definition of surface characteristics, samplings of at least five to fifteen percent of the.critical points from the gridded elevation models will be required, depending on the nature of the land surface.