| 摘要 |
<P>PROBLEM TO BE SOLVED: To facilitate accurate polygon formation. <P>SOLUTION: From an aerial photographic image or a satellite image, a changing boundary of color information by edge extraction is line-segmented to form a line-segment graphic of natural features on the earth. With altitude data superimposed on this graphic, a three-dimensional line-segment graphic of the object on the earth is obtained. A plurality of line-segments of this three-dimensional graphic are grouped by the same altitude level, with one altitude and the other of each of these line-segments made as attributes to determine directions in these line-segments by relative height difference. Then, the nearest starting point and ending point are connected in the line-segments of each group thus formed. <P>COPYRIGHT: (C)2004,JPO&NCIPI |
