World map on the equirectangular projection (or plane chart or Plate Carree). The graticule spacing is 10 degrees. This is a low resolution figure, unsuitable for zoom. The figure was produced in Inkscape 1.47 with (public domain ) data from the NGDC World Coast Line (on WGS84 datum). The red line is a rhumb. The black line is a great circle. Neither are straight. The Tissot ellipses indicate distortion: they apply to any meridian. True scale on all meridians and equator.The triangle is used on the Wiki Mercator projection page. The base (on equator) and the vertical (on meridian) are true to scale but Pythagoras gives the incorrect distance on the hypotenuse.
Own work
Peter Mercator