Based on TINs DEM, a new single-flow direction algorithm for topographic patterns extraction is proposed.

基于不规则三角网DEM，提出一种新的单流向地形特征自动提取算法。

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Each throng seems to be governed by a group mind and appears to be acting as a single organism, so quickly do they shift direction and flow into new shapes.

ENGADGET: Editorial: Tech is a flock of starlings

The currents of history may ebb and flow, but over time they move -- decidedly, decisively -- in a single direction.

WHITEHOUSE: President Obama Speaks to the Australian Parliament