包含着很多多边形，但是这些多边形大多永远被排除在视野以外，对于一个大型数据库，就像地形数据库来说是很重要的。

This can be very important for large databases that contain may polygons, most of which will not be in the field-of-view at any one time such as a terrain database.

youdao

包含着很多多边形，但是这些多边形大多永远被排除在视野以外，对于一个大型数据库，就像地形数据库来说是很重要的。

This can be very important for large databases that contain may polygons, most of which will not be in the field-of-view at any one time such as a terrain database.

youdao