| 摘要 |
A Digital Elevation Database is converted to a Polygon Database by creating square cells of varying sizes, starting with a minimum size cell. A center elevation point in the cell is used to form four three-dimensional triangles. The points within the cell are then tested against the flatness criteria. If the cell meets the flatness criteria it is expanded and tested again. This goes on until the cell fails the flatness criteria or a maximum specified cell size is reached. The cell parameters for the last trial cell meeting the flatness criteria or the maximum specified cell size are then entered into the polygon database. The points in the cell are then removed from the elevation database and the process starts over until all the points have been processed. In a second embodiment the procedure starts with a maximum size cell and the cell size is reduced until the cell meets the flatness criteria.
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