A new method for supporting interpretation of paleochannels in a large scale — Detrended Digital Elevation Model Interpretation.

In ancient China, the course of rivers changed frequently under the influence of the natural environment. The study of changes in paleochannels provides the basis for river regulation and water conservancy, and also supplies an important scientific foundation for the evolution of the geographical environment. However, it is extremely difficult to determine the location of paleochannels due to the limitations of traditional research methods and modern remote sensing interpretation. This paper introduces a new method, Detrended Digital Elevation Model Interpretation, for supporting interpretation of ancient rivers at large scales. A detrended DEM was obtained by removing the overall trend from the original DEM by subtracting a "detrending surface" derived from the original image using a guiding filter. The paleochannels of the Yellow River in the North China Plain were interpreted by GIS analysis with the help of historical materials. The detrended DEM was found to be less affected by the surface environment and had higher identification accuracy compared with an optical image and the colored DEM. Moreover, the detrended DEM could be used to interpret ancient rivers at large scales. Finally, the flow path of ancient rivers in the Eastern Han Dynasty (or near the Jindi River) was hypothesized using the interpretation results. The resulting paleochannel data can be used to revise historical river maps and provide reference for researching and managing the Yellow River. • Detrended Digital Elevation Model Interpretation is a new method for supporting interpretation of paleochannels in a large scale. • Detrending solves the ambiguity of feature details at low altitude of the original DEM by removing the down-valley slope of DEM. • The detrended DEM retains the topographic structure and shows the details of objects without being affected by the surface spectrum and occlusion. • The paleochannel of Yellow River in the Eastern Han Dynasty in Yanggu area is supposed to be located in the north side of Jindi river. [ABSTRACT FROM AUTHOR]