等高线回放法是数字高程模型(DEM)精度评估的重要方法之一,可以用于检测地形的保真程度,但是现有定量评估指标属于相对保真精度的范畴,因此基于水系和地形的固有套合特性,提出了水系和地形套合隶属度函数,从两者的套合程度实现DEM保真精度的定量化描述。首先,根据线状要素位移准则、尺度准则、平均坡度准则、最大套合偏移量准则和目视效果准则,运用模糊数学方法建立水系和地形套合隶属度函数;然后,使用4个不同地貌类型实验区域的1:5万地形图作为基础源数据,实验分析了DEM保真精度的评估。实验结果表明水系和地形套合隶属度函数不仅可以用于DEM保真精度的定量评估,而且可以用于DEM最佳分辨率的确定以及DEM尺度转换适宜范围的确定。

Reconstructing contours through a DEM is one of the methods of the DEM accuracy assessment. It can be used to detect terrain levels of fidelity. However, these methods show all a relative fidelity accuracy.Therefore, we present a membership function of the matching between drainage and terrain in this paper, we use the matching difference between drainage and terrain to quantitatively assess the DEM precision and to detect terrain levels of fidelity. First, we establish the matching offset membership function in accordance with the linear element displacement criterion, the scale criterion, the average slope criterion, the maximum matching offset criterion, and the visual effect criterion. Second, we use a 1:50 000 topographic map data of the four regions as the source data. Then the experiment of quantitative descriptive model of the matching precision explained how to use it in scaling transform of DEM. Finally, the experimental results show that the quantitative descriptive model of the matching precision not only can be used for the quantitative assessment of the extent of DEM terrain fidelity, but also can be used to determine the conversion of DEM scale appropriate range.