Projections

the functions of the anglescan package support the following map projections.

for a description of the different projections, see, for example, https://en.wikipedia.org/wiki/Map_projection

Selector | Projection | Function | Properties
--- | --- | --- | ---
kProjDist = 0 | azimuthal equidistant | r = c * theta | radius is proportional to polar angle.
kProjStereo = 1 | stereographic | r = c * tan theta/2 | circles on sphere map to circles.
kProjArea = 2 | azimuthal equal-area | r = c * sin theta/2 | preserves area measure.
kProjGnom = 3 | gnomonic | r = c * tan theta | great circles map to straight lines.
kProjOrtho = 4 | orthographic | r = c * sin theta | k-space mapping in ARPES and LEED.

the projections in this package are defined for 0 <= theta < 90.