Grainflows produce temporary geomorphological signatures on the slipfaces of aeolian dunes, and are a fundamental agency by which dunes migrate. The purpose of this study is to present an algorithm to objectively and efficiently delineate grainflow boundaries by processing Digital Elevation Models (DEMs) in Matlab and ArcGIS. Grainflows can be identified by analyzing temporal changes in slipface elevation, and the morphology can be extracted by defining the boundary that encloses the area of movement. The method allows large numbers of grainflows to be quickly and objectively delineated and extracted from LiDAR data. The process avoids the subjective nature of manual measurement, thereby improving the commensurability of different grainflow regimes in both terrestrial and extraterrestrial environments. The algorithm is presented here in the context of analyzing grainflows and related processes on the slipfaces of dunes, but it is applicable over the broader scope of other forms of slope failure and geophysical flows, such as avalanches, snowslides, landslides, and debris flows.

沙流在风沙丘的滑移面上产生临时的地貌特征，是沙丘迁移的基本机构。这项研究的目的是提出一种算法，以通过在Matlab和ArcGIS中处理数字高程模型（DEM）来客观有效地勾勒出颗粒流边界。可以通过分析滑动面高程的时间变化来识别颗粒流，并可以通过定义包围运动区域的边界来提取形态。该方法可以快速，客观地描绘并从LiDAR数据中提取出大量的谷物流。该过程避免了人工测量的主观性质，从而提高了陆地和陆地外环境中不同颗粒流态的可比性。