数字高程模型坡度误差指标尺度转换分析

Analysis of Slope Error Indices Derived from Digital Elevation Models at Different Scales

针对我国大比例尺DEM数据库尚未建成,但是国家的生产建设又需要1∶5 000DEM所提取的地形因子(如坡度),而目前少有对1∶5 000比例尺DEM转换研究的现状,该研究制定出适合福建全省不同比例尺DEM提取地形因子间互相转换标准。选取福建省典型地貌(山地、丘陵、平原)共7个样区为实验样区,使用python脚本来批量提取7个样区在5种比例尺DEM下的多种地形因子,选取坡度作为研究对象,提出适合中小比例尺DEM向大比例尺DEM转换的3个误差指标:坡度面积、坡度信息熵、坡度鉴别信息,得出1∶10 000、1∶50 000、1∶250 000、1∶500 000DEM所提取坡度因子向1∶5 000转换的定量表达式,制定出中小比例尺DEM提取坡度因子向大比例尺DEM对应因子的转换标准。

In view of the fact that large scale DEM database has not yet been built in our country, this study developed a suitable method for mutual transformation between terrain factors derived from different scale DEMs of Fujian Province. This article selected seven experimental sample areas with typical landforms which are mountains, hills and plains in Fujian Province. It used the python scripts to batch extract multiple terrain factors of seven regions under five different scale DEMs,and selected slope as the research object. The study results put forward three error indices that are suitably converted from small or medium scale DEMs to large scale DEM. The three error indices are slope area,slope information entropy,and detecting information. The study obtained the quantitative expression of corresponding slope factors from DEM at scales of 1 ： 5000, converted from DEMs at scales of 1 ： 10 000,1 ： 50 000,1 ： 250 000, and 1 ： 500 000, and made the conversion standard of slope factors extracted from medium or small scale DEMs to corresponding factors from the large scale DEM.