等值线图是用布满一定区域内的若干条等值表示某地理现象的数量及分布状况的图形。由于等线标有数值,而且数值间隔是相同的,所以可以根据等值线的数值大小、疏密程度、排列的方向、形状变化等反映出该地理事物变化的急缓、递变的方向及分布特点等。1“高与低”等值线弯曲的普遍规律——凸高为低,凸低为高。凸高为低,是指等值线的弯曲部位向高值凸出,即每条等值线弯曲的 Contour map is covered with a certain area within a certain number of equivalent representation of the number of geographic phenomena and distribution of graphics. Since the isobars have numerical values ​​and the numerical intervals are the same, the rapid and gradual change of the geo-physical changes can be reflected according to the numerical value of the contour, the degree of density, the direction of arrangement, and the shape change Distribution features. 1 “high and low ” Contour bending common law - convex high is low, convex low is high. The convex height is low, means that the curved part of the contour line protrudes to a high value, that is, each contour line is curved