plot2sphere: Draws a sphere plot
plot2sphere draws plots in an isotropic 3-dimensional space
using spherical polar coordinates.
The plotting volume is a cube,
which is viewed from the outside and usually bounded by a
wire frame annotated by Cartesian coordinates.
This viewing cube is not necessarily centered on the coordinate origin.
This plotting geometry is like that used by
but the coordinate unit size is always the same in the three dimensions,
and the coordinates are specified differently.
Positional coordinates are specified as
plot2sphere layer1=mark in1=survey.fits lon1=RA lat1=DEC r1=REDSHIFT
Content is added to the plot by specifying
one or more plot layers using the
N part is a suffix applied to
all the parameters affecting a given layer;
any suffix (including the empty string) may be used.
Available layers for this plot type are: