Thirdly, according to the research needs, selected gully length, gully width, gully density and vertical slope as the evaluation index.

根据本研究的需要，选取沟道长度、沟道宽度、沟壑密度和纵比降作为分析沟道变化的判别指标。

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Thirdly, according to the research needs, selected gully length, gully width, gully density and vertical slope as the evaluation index.

根据本研究的需要，选取沟道长度、沟道宽度、沟壑密度和纵比降作为分析沟道变化的判别指标。

youdao