传统的方法是寻找“等距-等多普勒”单元面积的闭合形式的解析表达式。
By the traditional means, people tried to search for a closed form of the analytical expression of the "range doppler" cell's area.
并给出一近似公式。以便使用者选择恰当的单元面积，或检查已划分好的单元面积是否能满足精度要求。
Approximate formula is given to help the user to choose the right area of element or to see that the divided area of element meets the precision requirements.
通过分析研究各县区不同地貌单元面积，在假定县内道路分布均一的情况下，计算了各县区侵蚀参数和区域道路开挖边坡的年侵蚀量。
Based on the composition of landform of each country, and an assuming of that the distribution of highway is similar, the erosion parameter and cutting slope erosion are analyzed.
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