Van der Grinten I Projection
Polyconic
vgrint1
Central Meridian: A straight line.
Meridians: Circular curves spaced equally along the equator and concave toward the central meridian.
Parallels: The Equator is a straight line. All other parallels are circular arcs concave toward the nearest pole.
Poles: Points.
Symmetry: About the Equator or the central meridian.
In this projection, the world is enclosed in a circle. Scale is true along the Equator and increases rapidly away from the Equator. Area distortion is extreme near the poles. This projection is neither conformal nor equal-area.
There are no standard parallels for this projection.
This projection was presented by Alphons J. Van der Grinten in 1898. He obtained a U.S. patent for it in 1904. It is also known simply as the Van der Grinten projection (without the “I”).
Mapping Toolbox™ uses a different implementation of the Van der Grinten I
projection for displaying coordinates on map axes than for projecting
coordinates using the projfwd
or projinv
function. These
implementations may produce differing results.
The implementation of the Van der Grinten I projection for displaying
coordinates on map axes is applicable only for coordinates that are referenced
to a sphere. The implementation of the Van der Grinten I projection for
projecting coordinates using the projfwd
or projinv
function is applicable for
coordinates referenced to either a sphere or an ellipsoid.
This projection is available only for the sphere.
landareas = shaperead('landareas.shp','UseGeoCoords',true); axesm ('vgrint1', 'Frame', 'on', 'Grid', 'on'); geoshow(landareas,'FaceColor',[1 1 .5],'EdgeColor',[.6 .6 .6]); tissot;