Some New Methods of Topologic Classification of Channel Networks

C. Verner and J . S . Smart* Some N e w Methods of Topologic Classification of Channel Networks Abstract Some new methods for the topologic classification of channel networks are proposed. These methods are all based on the concept of topologic path length, or number of links from the network outlet to a junction or source. Two param- eters, the total path length (sum of all path lengths) and the diameter (largest path length) are shown to be useful in network analysis. Some advantages of these parameters are that they are easy t o measure, have straightforward to- pologic interpretations, and are closely related to important geometric measures. Moreover, they are capable of explaining various empirical geomorphic “laws,” such as the 0.6 power relation between mainstream length and area. I. TOPOLOGICALLY DISTINCT CHANNEL NETWORKS I n the quantitative analysis of drainage networks, it is convenient to choose for study the set of all channels above a given point in the drainage system, i.e., all channels that contribute to the discharge at that point. If the channels are idealized as single lines, the resulting figure is known in the geomorphological * The research for this paper was supported in part by the Geography Programs, Office of Naval Research. C. Werner i s professor of geography at the University of Califom% at Zrvine (Wallace J . Eckert Fellow at the IBM Watson Research Center during the time of the preparation of this paper); J . S. Smart is research stafl member at the Thomas J . Watson Research Center, Yorktown Heights, N.Y.