Technical schematic display system utilizing preassigned component detail levels

A schematic display system for displaying selected areas of interest of a schematic includes a display screen, preprocessed display data stored in a data structure, and a digital processor for controlling the level of detail of the display in accordance with level of detail values preassigned to component primitives of the schematic objects. The level of detail values are, in part, a function of the resolution of the display screen, and are selected to display details of the schematic as such detail would become visually meaningful to a human user of the system. The system includes provision for user defined restricted schematics which eliminate objects, connections, etc. from that display (but not from the basic underlying schematic) as specified by the user. It also includes provision for custom schematics which simultaneously display areas of interest on the screen, the displayed areas of interest being non-adjacent areas, areas from different functional schematics (electrical and structural), etc. based on the basic underlying schematic(s). Both restricted schematics and custom schematics are stored economically for future selection and retrieval. The system allows the user to change the displayed scale of the area of interest, while keeping the center of view on the schematic substantially constant as the displayed scale is changed.