在田中央拉一直綫AB(我叫它做准綫)。把准綫等分成n等分,每份長为m,量出各分点的田寬为H_1,H_2,…,H_(n-1),則田面积S=m(H_1+H_2+H_3++…+H_(n-1))。这种方法是根据辛卜孙近似求积法来的,辛氏的方法是欲求曲綫PM与直綫AB所圍成圖形PMBA的面积,將AB等分成AA_1=A_1A_2=…A_(n-1)A_n==m, In the center of the field pull straight AB (I call it as a guideline). Divide the guideline into n equal parts, each length is m, measure the field width of each sub point as H_1, H_2,..., H_(n-1), then the field area S=m(H_1+H_2+H_3++... +H_(n-1)). This method is based on the Sibin Sun approximate quadrature method. Sin’s method is to plot the area of ​​the PMBA between the curve PM and the straight line AB, dividing AB into AA_1=A_1A_2=...A_(n-1)A_n ==m,