森林调查时需要计算小班、林班、抽样调查总体以至林场、林业局的面积。通常在求算面积时,先以现地测量或航空象片转绘成图,然后在图上用各种方法,例如坐标法、图解法、网点板法、平行线板法和求积仪法等量算 Forest surveys need to be calculated in small classes, forest classes, sample surveys as a whole and even the area of ​​forest farms and forestry bureaus. Usually in the calculation of the area, first with the local measurements or aerial photo transfer mapping, and then on the map by various methods, such as coordinate method, graphic method, the dotted board method, the parallel plate method and the quadrature method Isometric calculation