这个椭球面的中心和方位就构成了我们所说的大地基准面。

The center and orientation of the ellipsoid is what we call the datum.

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本文阐明了当工件以回转面定位，计算定位误差时，取定位基准或为回转面某一母线，或为其中心线，计算结果是相同的。

With workpiece located by its rotary surface , either the rotary surface or its center line is regarded as the reference of location , the calculating results of location error are the same.

youdao

本文阐明了当工件以回转面定位，计算定位误差时，取定位基准或为回转面某一母线，或为其中心线，计算结果是相同的。

With workpiece located by its rotary surface , either the rotary surface or its center line is regarded as the reference of location , the calculating results of location error are the same.

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