Pseudoconical projection



Pseudoconic projections are similar to conic projections in a way that their parallels are partial concentric circles. The difference from conic projection is that meridians are curved rather than straight. The meridians are equally spaced. The outline is approximately heart-shaped.


 * Bonne in this projection the parallels of latitude are concentric circular arcs, and the scale is true along these arcs. On the central meridian and the standard latitude shapes are not distorted. The Bonne method has fallen into disuse, giving way to the transverse Mercator method. However, it is still a credible way to preserve shapes and areas. Distortions are are noticeable the further away from the center of the map. The scale is only accurate along the vertical axis.


 * Werner cordiform designates a pole and a meridian; distances from the pole are preserved, as are distances from the meridian (which is straight) along the parallels.


 * Continuous American polyconic refers to those projections whose parallels are all non-concentric circular arcs, except for a straight equator, and the centers of these circles lie along a central axis. This description applies to projections in equatorial aspect.