使用方法：
1、　输入AP命令，在对话框中浏览并加载“面积求和.LSP”。
2、　输入ZMJ（总面积的拼音首字母）命令调用程序。
3、　根据提示选择要计算面积的各个图形。选择结束后就会得到面积之和。
注意：尽量选择封闭的多段线、样条线，不封闭也可以求面积，但结果意义不大(Usage method:

1, enter the AP command, browse and load "area summing.LSP" in the dialog box.

2, enter the ZMJ (total area Pinyin initials) command calling procedure.

3, according to the prompts, choose the graphics to calculate the area. When the choice is over, the sum of the area will be obtained.

Note: Choose the closed multi-section lines and splines as far as possible. You can find the area without closing, but the result is not significant.)