Zenithal Stereographical Equatorial Projection
 Lines of Latitude •Equator •Latitudes Lines of Longitude •Prime Meridian •Longitudes Relationships Facts on Earth Zenithal Projections •Gnomonic Polar •Gnomonic Equatorial •Stereographic Polar •Stereographic Equatorial •Orthographic Polar •Orthographic Equatorial Simple Conic Projection Cylindrical Equal-area Projection References Figure A Figure B                           Figure C Figure D Stereographic projections are created by projecting from a point at one end of the diameter in a circle to a projection plane which sit tangential to the other end of the diameter. This situation is clearly depicted in Figure A where the light source comes from point A with white rays radiating out of it. Geometrically, the light source sits on the left side of the diameter AB. In terms of geography, the light source sits on the equator of the earth opposite to the tangential point that the projection plane CI makes with the equator. Such characteristics make the projections on this plane a equatorial projection. When viewed in this perspective, parallels are seen as the horizontal arcs in Figure D, which is equivalent to the red arc CD in Figure B. The derivation of such arcs is as follows: In general, the projection of latitudes in the stereographic equatorial projection is created by rotating a line of length CE on point E. So long as this line touches the white circle (which represents the earth), a path of points is drawn at the end of CE to create a projected parallel on the plane. With EG representing the polar axis and AB representing the equator, one knows that the two lines intersect perpendicularly. As such,