墨卡托投影，与地轴方向一致的圆柱切于或割于地球，按等角条件将经纬网投影到圆柱面上，将圆柱面展为平面后，得平面经纬线网。投影后经线是一组竖直的等距离平行直线，纬线是垂直于经线的一组平行直线。各相邻纬线间隔由赤道向两极增大。一点上任何方向的长度比均相等，即没有角度变形，而面积变形显著，随远离标准纬线而增大。-Mercator projection is consistent with the direction of the Earth s axis cylinder cut in or cut in the earth, according to isometric conditions graticule projected onto the cylindrical surface, the cylindrical surface will show a flat, too flat weft wire mesh. After the projection is a vertical warp equidistant parallel lines, perpendicular to the weft of a set of parallel warp line. Adjacent weft spacing increases from the equator to the poles. That the ratio of the length in any direction are equal, i.e., there is no perspective distortion, deformation of the area significantly increases the standard parallel with distance.