| 摘要 |
PROBLEM TO BE SOLVED: To provide a numerical map data processing method for expressing a landform in topographic indices composed of a plurality of elements on the basis of a numerical map so as to create a map with excellent visibility. SOLUTION: An altitude value k at each lattice point E is read from numerical map data 50. A range constituted of a plurality of lattice points E surrounding the central lattice point is set to be a nearby range NA. Out of the altitude values k of all the lattice points E in the nearby range NA, a peak contact altitude value k<SB>max</SB>and a valley contact altitude value k<SB>min</SB>are read and, from the expression R=(k-k<SB>min</SB>)/(k<SB>max</SB>-k<SB>min</SB>), a ratio altitude value R is calculated. Next, on the basis of the altitude value k of each lattice point E, the tilt angleθof the slope of each lattice point E is calculated. Then, for every lattice point E, a topographic index T is calculated from the expression T=log(k×tanθ×R). Then, color image data are calculated from the topographic index T for every lattice point E and, by making the color image data correspond to lattice point by an operation such as pasting the color image data to each lattice point E, a topographic map is created, displayed on a display section 5 and outputted by an output section 6. COPYRIGHT: (C)2010,JPO&INPIT
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