| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to maintain the visibility of the positions and shapes of various kinds of symbols on a map without being affected by the positions of a visual point and steady gaze point at the time of making perspective transformation of the map and displaying the map by providing the device with a coordinate conversion means and three-dimensional symbol forming means. SOLUTION: A conversion matrix M1 for executing coordinate conversion from a map coordinate system to a visual point coordinate system and a conversion matrix M2 for executing perspective transformation in the visual point coordinate system are determined from the coordinates of the visual point and steady gaze point instructed by a mouse 30. The values of the respective components of M1, M2 are calculated and are previously arranged in a memory 60. Next, the records in the map data of an external memory device 10 are fetched. The matrix M1 is acted on the reference point coordinates by a processor 50 if the fetched records are symbol records. The processing to form a 'flag' is executed in the visual point coordinate system and thereafter, the matrix M2 is acted on the respective resulted coordinate points. Respective graphics and characters are finally plotted on a graphic display 20 by using the coordinate values obtd. by the processing. |
