建立数据库的核心环节是面积计算，其中TBMJ-XZDEMJ-LXDWM

The core part of building a database is the area calculation, where TBMJ-XZDEMJ-LXDWMJ-field area = map spot land area, (TBMJ-XZDEMJ-LXDWMJ) × field factor = field area Because the data is spatially superimposed, the patches will be cut, so the area of ​​the patches will also change, causing the linear features of the patches to be redistributed between the patches.

The core link of establishing the database is the area calculation, in which TBMJ-XZDEMJ-LXDWMJ-Tiankan area is the area of the map-spot di-class, (TBMJ-XZDEMJ-LXDWMJ) x Tiancan coefficient-Tiankan area. Because the data is spatially superimposed, the spot is cut, so the area of the spot will also change, resulting in the line of the spot needs to be redistributed between the spots.

The core link of establishing database is area calculation, in which tbmj-xzdemj-lxdwmj-ridge area = map spot area, (tbmj-xzdemj-lxdwmj) × ridge coefficient = ridge area. Because the data will be cut after spatial superposition, the area of the map will also change, resulting in the linear features of the map need to redistribute the area between the map spots.<br>