| 摘要 |
PURPOSE:To execute a projection transformation with a quadratic coordinate transformation and to prepare a birds-eye view at sufficiently practical speed even at a personal computer level by executing the projection transformation necessary for the preparation of the bird-eye view in a bearing direction and a height direction separately. CONSTITUTION:The projection transformation in the bearing direction is executed to the height information and the point-of-view information of a read grid shape and grid point by a projection transform part 2 and the result is stored into a grid shape storage part 4. Next, the projection transformation in the height direction is executed to the above-mentioned input information and the result is stored into a height information storage part 3. A display sequence determining part 5 uses the grid shape after the projection transformation held in the grid shape storage part 4, determines the display priority sequence of graphics to express a grid plane and stores the result into a display sequence storage part 8. Concerning the grid plane designated by a pointer, the grid shape after the projection transformation and the height information held in the grid shape storage part 4 are extracted. |
