Wagner IV Projection
Central Meridian: Straight line half as long as the Equator.
Other Meridians: Equally spaced portions of ellipses concave toward the central meridian. The meridians 103º55' east and west of the central meridian are circular arcs.
Parallels: Unequally spaced straight parallel lines, perpendicular to the central meridian. Spacing is greatest toward the Equator.
Poles: Lines half as long as the Equator.
Symmetry: About the central meridian or the Equator.
This is an equal-area projection. Scale is true along the 42º59' parallels and is constant along any parallel and between any pair of parallels equidistant from the Equator. Distortion is not as extreme near the outer meridians at high latitudes as for pointed-polar pseudocylindrical projections, but there is considerable distortion throughout the polar regions. It is free of distortion only at the two points where the 42º59' parallels intersect the central meridian. This projection is not conformal or equidistant.
For this projection, only one standard parallel is specified. The other standard parallel is the same latitude with the opposite sign. The standard parallel is by definition fixed at 42º59'.
landareas = shaperead('landareas.shp','UseGeoCoords',true); axesm ('wagner4', 'Frame', 'on', 'Grid', 'on'); geoshow(landareas,'FaceColor',[1 1 .5],'EdgeColor',[.6 .6 .6]); tissot;