台灣數值高程模型之建立及精度分析

A digital Elevation model of Taiwan and accuracy assessment

本文以農林航測所提供之高程資料，以最小曲率法製作成3秒網格之DTM（約90公尺解析度），再以一等一級水準點及一、二等衛星控制點之高程檢核之，於水準點上，DTM之高程誤差均值約為14公尺，標準偏差為13公尺，而於衛星點上，其誤差均值及標準偏差分別為18及17公尺。本文以諧和面法用水準點及衛星點上之高程製作一平滑的修正面，而得一修正後之DTM，其高程與真高程之差異降低到4公尺左右（均方差）。本文之DTM採用TWD97座標系統，可透過申請向內政部取得此DTM及應用程式。 A digital terrain model (DTM) on a 3′′× 3′′ grid (a 90-m horizontal resolution) was created by the minimum curvature method using elevation data from the Institute of Agricultural and Forestry Aerial Survey. Elevations on the first-order leveling benchmarks and satellite control points were used to assess the accuracy of the DTM. On the benchmarks, the mean error and the standard error of the DTM elevations are 14 m and 13 m, respectively, while on the satellite control points, the corresponding values are 18 m and 17 m. A correction surface was constructed by a harmonic surface method using the elevation differences on the benchmarks and satellite control points, and this surface was then used to refine the raw DTM. The RMS error of the elevations of the refined DTM is 4 m. The DTM model adopts the TWD97 coordinate system and is available at the Ministry of the Interior.

A digital terrain model (DTM) on a 3''× 3'' grid (a 90-m horizontal resolution) was created by the minimum curvature method using elevation data from the Institute of Agricultural and Forestry Aerial Survey. Elevations on the first-order leveling benchmarks and satellite control points were used to assess the accuracy of the DTM. On the benchmarks, the mean error and the standard error of the DTM elevations are 14 m and 13 m, respectively, while on the satellite control points, the corresponding values are 18 m and 17 m. A correction surface was constructed by a harmonic surface method using the elevation differences on the benchmarks and satellite control points, and this surface was then used to refine the raw DTM. The RMS error of the elevations of the refined DTM is 4 m. The DTM model adopts the TWD97 coordinate system and is available at the Ministry of the Interior.