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网点板已广泛用于求定地图或航空像片上的面积。网点的间隔可用点密度(D)或单位面积(即每平方时)的点数来表示。把网点板盖在一块面积上,记数落在该面积上的点数(N)来求这块面积。估计的地图面积是N/D个面积单位(即平方时,1吋~2=6.45cm~2),应根据地图比例尺将其换算为地面面积。尽管容易得到整个面积的估计值,但并不知道估计误差。应该知道这种误差,这不仅是由于它本身的必要性,估计其它森林特征数时
Hood board has been widely used to determine the area on the map or aerial photo. The interval between dots can be expressed as the dot density (D) or the number of dots per unit area (ie, per square). Cover the gusset plate over an area and count the number of points (N) that fall on the area to find the area. The estimated area of the map is N / D units of area (ie, 1 to 2 = 6.45 cm 2 for squared) and should be converted to floor area based on the map scale. Although it is easy to get an estimate of the entire area, no estimation error is known. This error should be known, not only because of its own necessity, but also when estimating other forest characteristics