麦卡托投影法(Mercator projection)，又称麦卡托投影法、正轴等角圆柱投影，是一种等角的圆柱形地图投影法。本投影法得名于杰拉杜斯·麦卡托，法兰提斯出身的地理学家、地图学家。他于1569年发表长202公分、宽124公分以此方式绘制的世界地图。在以此投影法绘制的地图上，经纬线于任何位置皆垂直相交，使世界地图可以Штгтгтштгтгтгтштсуц绘制在一个长方形上。由于可显示任两点间的正确方位，航海用途的海图、航路图大都以此方式绘制。在该投影中线型比例尺在图中任意一点周围都保持不变，从而可以保持大陆轮廓投影后的角度和形状不变（即等角）；但麦卡托投影会使面积产生变形，极点的比例甚至达到了无穷大。

The Mercator projection is a cylindrical map projection presented by the Flemish geographer and cartographer Gerardus Mercator in 1569. It became the standard map projection for nautical purposes because of its ability to represent lines of constant course, known as rhumb lines or loxodromes, as straight segments that conserve the angles with the meridians. Although the linear scale is equal in all directions around any point, thus preserving the angles and the shapes of small objects (which makes the projection conformal), the Mercator projection distorts the size of objects as the latitude increases from the Equator to the poles, where the scale becomes infinite. So, for example, landmasses such as Greenland and Antarctica appear much larger than they actually are relative to land masses near the equator, such as Central Africa.