Layout of data structures based on relationships between the data structures

A rectilinear layout system creates a diagram (graph) from information about items (nodes) and relationships among the items, such as the information which defines data bases, computer networks, and object based systems. The rectilinear layout system designates one of the items as a focus node and partitions the remaining items into clusters (sub-graphs) of related nodes. Multiple location groups are created that are relative to the focus node for the graph and each sub-graph is assigned to a location group. The rectilinear layout system then plots a location for each node in each of the sub-graphs by recursively iterating through the sub-graphs, designating focus nodes for each sub-graph, creating lower level sub-graphs, and assigning the lower level sub-graphs to location groups relative to the corresponding focus node until a lower level sub-graph contains only a single node. At that point, the rectilinear layout system plots the single node on to a layout surface for the lower level sub-graph and returns up a level. Once all nodes in a sub-graph have been plotted, the rectilinear layout system routes connectors among the nodes to represent the relationship among the nodes. The rectilinear layout system continues its recursive functions until all sub-graphs have been laid out. The rectilinear layout system then plots absolute coordinates for the focus node for the graph, the nodes of the sub-graphs, and the connectors within the sub-graphs, and creates connectors among the focus node for the graph and the appropriate nodes of the sub-graphs. Data structures for managing the information at each sub-graph level are also described as is a particular arrangement of computer software modules for implementing the rectilinear layout system.