articles: Areas, nodes and networks: Some analytical considerations

This situation has been identified in the literature as the `self potential' problem. In this article, integration over continuous space within the origin-destination zones is applied to not only compute the intrazonal flows more accurately, but also to evaluate the interzonal flows along shortest path routes meeting the interzonal links at efficient intermediate points. In particular, this general approach permits more accurate corrections to the conventional model, allowing, for instance, the usual approximations in determining average trip length to contiguous zones to be overcome. The eventual aim is to develop practical `rules of thumb' for correcting the conventional analysis. This article also examines facility choice via alternative round trip routes, attempting to discern the influence of `intervening opportunities' on the potential for multi-stop trips without having to fully identify the actual trip chain. Such intervening opportunities can only be properly considered along the alternative paths of the actual network.