ライン勾配データのラスター化と地図作成

概要

論文の詳細を見る
We have developed methods with which to generate a raster slope-gradient map from a line slope-gradient map produced with C-BATM (Contour-Based Automatic Terrain Mapping). C-BATM, utilizing digitized contours, generates fall lines from each of digitized points of contours and calculates a gradient between two consecutive contours, similar to the procedure with manual measurements. Rasterization of the line slope-gradient is necessary in order to utilize the output map by the C-BATM in overlay analyses, which commonly employs a data set in raster format. Two methods were considered. Method I identifies the nearest slope-gradient line within a search radius R (R=d/√<2> ; d, grid spacing) of the grid point and assigns this value (Program RL-N). Method 2 uses all the lines of slope-gradient within R and takes a mean (Program RL-M). We tested these algorithms with digitized contours of Yakushima, from which grid-based DEMs for traditional methods were also generated for comparison. Employing different grid-cell sizes to see the scale effect and also shifting the grid points, we examined the robustness and reliability of the methods by producing distribution maps, histograms and statistics. The Program RL-M produced maps in which a regional distribution pattern is best revealed, while the Program RL-N yielded histograms close to the normal distribution. The results indicate that changes in statistics obtained by the proposed methods are small, and our methods are more robust and reliable than the traditional methods using gridbased DEMs for generating a raster slope-gradient map.
日本地形学連合の論文
2004-01-25

ライン勾配データのラスター化と地図作成

スポンサーリンク

概要

著者

関連論文

スポンサーリンク