Method and apparatus for searching line data in graphic data base system.

摘要

A method for searching line data (7) to be transmitted to a terminal (6) which demands an output map. The line data (7) is obtained by selecting line segments within an output domain (2) from the entire line data (3) included in an object map (1) read from a graphic file (4). The selection of the line segments is performed by obtaining the coordinates of intersections (Pi') of lines specifying the output domain (2) and line segment specified by any two adjacent characteristic points (Pi) on a line associated with line data read out from the graphic file, and then by arranging the intersections (Pi') and the characteristic points (Pi) within the output domain (2) sequentially along the line. This makes it possible to shorten the response time between a demand from the terminal (6) and the actual output of the line data (7) within the output domain (2) to that terminal.