A primary first step in defining the functional capabilities of a given microcirculatory bed is to describe the distribution of intravascular pressure and flow throughout the network using an idealized geometrical model. By applying an approach developed by the geomorphological sciences, changes in vessel lengths, numbers, and diameters were systematically related to order number by applying three mathematical relationships. From measurements of a number of vascular modules, generalized relationships were obtained which applied to the microcirculation as a whole. An idealized model was developed by the computer-generation of node-node connections based on their probabilities of occurrence, and by generation of lengths and diameters, based on equations relating diameter and length to branching order number. Networks of this type were readily analyzable in terms of pressure-flow characteristics, using linear network analysis techniques. The current study focused on two specific microvascular beds: [1] rabbit omentum, in which numerous studies have related in vivo pressures and flows to geometry, and [2] human bulbar conjunctiva, in which quantitative data is almost totally nonexistent. In view of the close correlation between measured and predicted omental pressure and flow values, it was apparent that the current modeling scheme offered a close approximation to in vivo values. A more significant application, however, is in the correlation of complex alterations in vascular geometry with the accompanying hydrodynamical changes.