There maybe many layers in a database, e. g. soil type, elevation, land use, land cover.

一个数据库中可能有许多层，例如土壤类型、海拔、国土利用、国土覆盖。

youdao

There maybe many layers in a database, e. g. soil type, elevation, land use, land cover.

一个数据库中可能有许多层，例如土壤类型、海拔、国土利用、国土覆盖。

youdao