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What's a path worth? To quantify this characteristic -- which is really the traffic potential of each path -- we have to make a few assumptions. The first is that pedestrians take generally straight paths across campus. Though it is certainly not the case that people walk "as the crow flies," individual deviations probably approximate straight paths in the aggregate. The second assumption is that traffic to and from campus buildings is proportional to their populations. For residence halls, we use occupancy; for class buildings, we use classroom capacity; for off-campus housing, we use East Lansing census data. The third is that the influence of population diminishes with distance. Travelers located in more distant buildings have more path options, many of them not involving our field at all; these include the options to eschew walking altogether and go by bus or car. With these assumptions in mind, and with eight nodes to work with, we extend 45° zones of influence out in straight lines from each node. These are shown in the image to the left. Based on our premises -- that people walk in generally straight lines, that traffic is directly proportional to population, and that traffic is also inversely proportional to distance -- the so-called gravity model seems a likely choice for our calculations. So how's that gonna work? >> |