三种河流相对高程模型生成方法对比

长安大学地球科学与资源学院,西安 710054

相对高程模型(REM);数字高程模型(DEM);核密度法;反距离加权法(IDW);横截面插值法

Comparison of Three Methods for Generating Relative Elevation Models of River
LI Yue1,2,3,CHAO Huixia1,2,3,XIN Yonghui1,2,3,WANG Xingwei1,2,3,WANG Ran1,2,3

1.School of Earth Science and Resources , Chang'2.an University , Xi'3.an 710054, China

REM; DEM; Kernel density method; Inverse distance weighting(IDW)method; Cross section interpolation method

DOI: 10.13512/j.hndz.2023.01.14

备注

相对高程模型(REM,RelativeElevationModel的缩写)表示相对于河流水面或活性河道的海拔高度,衍生于数字高程模型(DEM,DigitalElevationModel的缩写),能够消除因河流纵向的地势造成的DEM表征不清楚,高差过大造成细节模糊地势的影响,从而在平面图上更为清晰地表征河流地形的细微变化,因而研究REM的生成方法及其适用性具有十分重要的意义。通过文献综述,选取美国加利福尼亚州内华达山脉的卡森河某河段为实验区,利用其高精度(米级分辨率)DEM数据,介绍核密度法、反距离加权法、横截面插值法三种REM生成方法。通过REM和DEM的对比,以及三种REM的效果对比,得出:当高程差过大时,DEM可视化方案往往不能很好地在河流地貌刻画中发挥作用,尤其是在解译时,利用REM可解决高差过大造成的细节模糊问题;横截面插值法主要的优势表现在可根据用户需要做适用性调整,相对而言鲁棒性强,较为灵活,但其自动化程度较低,且花费的时间较长,因此需较多的人工干预;核密度法耗时相对较少,REM结果很少有伪影或错误的相对高程值,但核密度法导致一些潜在的伪影或者错误的相对高度,体现在研究河段范围的终点会有偏差;反距离加权法(IDW,InverseDistanceWeighted的缩写)的优势是创建用时较少,且只需要输入两个数据:DEM和河流中心线,但因搜索距离问题不合适易在特殊地段出现失效情况。因此,REM将在河流精细刻画中发挥重要的作用,其生成方法已经可以实际应用,但有待进一步提高和完善;REM模型不需经过复杂计算,适合难以进行现场调查的河流对比研究,且应用范围较广,为河流迁移、洪水分析、河流管理和修复、生物栖息地选取以及文化评估方面的研究提供了重要作用。
The relative elevation model(REM, abbreviation for Relative Elevation Model)represents the altitude relative to the river surface or active river channel, which is derived from the digital elevation model(DEM, abbreviation for Digital Elevation Model),and can eliminate the influence of unclear DEM representation caused by the longitudinal terrain of the river and the blurred terrain caused by the large height difference, so that the subtle variations of river topography can be more clearly represented on the floor plan. Therefore, it is of great significance to study the generation method and applicability of REM. Through literature review,this paper selects a section of the Carson River in the Sierra Nevada,California,USA as the experimental area,and uses its high-precision(meter-level resolution)DEM data to introduce three REM generation methods: kernel density method, inverse distance weighting method, and cross section interpolation method. Through the comparison of REM and DEM,as well as the comparison of the effects of three REMs,it is concluded that:When the elevation difference is too large,the DEM visualization scheme often cannot play a good role in the characterization of river landforms, especially in interpretation,while using REM can solve the problem of blurred details caused by excessive height difference;the main advantage of the cross section interpolation method is that it can be adjusted according to the needs of users with relatively strong robust and more flexible,but its degree of automation is low and it takes a long time,so it requires more manual intervention;the kernel density method is relatively less time-consuming,and the REM results rarely have artifacts or wrong relative height values,but the kernel density method leads to some potential artifacts or wrong relative heights,which are reflected in the deviation at the end of the study river range;the advantage of the inverse distance weighted method(IDW,abbreviation for Inverse Distance Weighted)is that it takes less time to create, and only needs to input two data: DEM and river centerline, but it is easy to fail in special areas due to inappropriate search distance. Therefore, REM will play an important role in the detailed description of rivers, and its generation method has been practically applied, but needs to be further improved and perfected. The REM model does not require complex calculations, and is suitable for comparative studies of rivers that are difficult to conduct on-site investigations, which has a wide range of applications and plays an important role in the research on river migration, flood analysis, river management and restoration, biological habitat selection,and cultural assessment.
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