DEM地形信息量计算的不确定性研究

DEM地形信息量的准确度量是判定DEM数据应用适宜性与限制性关键。以黄土丘陵沟壑区DEM及其派生的坡度、坡向DTM为例进行实验,研究子集划分与分级数对DEM信息量估算精度的影响。结果表明,DEM地形信息量是实际地形信息和子集划分策略共同作用的结果,现有DEM信息量计算存在不确定性,DEM子集划分算法和分级数的选择直接影响DEM信息量的计算结果。文章借助最大熵定理的基本思路构建DEM地形信息量分级判定模型,可客观获得连续型栅格地形数据在信息量计算上最优分级,为有效估算DEM地形信息量提供科学依据。

Uncertainty of Terrain Information Content Based on Grid DEM

Precision of DEM terrain information content is a key factor to judge the applicability and limit of DEM data. An experiment is designed to find out the effect of DEM subset partition strategy and number of subsets to the estimate precision of DEM terrain information content based on DEM, slope and aspect data of hilly and gully test areas on the Loess Plateau. The result shows that DEM terrain information content is affected by both terrain information and subset partition strategy. To weaken the uncertainty of DEM terrain information content calculated by traditional algorithms, this paper presents a DEM subset partition model based on the maximum entropy theorem. It provides an objective theoretical basis for DEM information content calculation and has been proved efficient to avoid the subjectivity and arbitrariness in DEM artificial classification.