The pixelization used by the transforms is defined by the entries of the S2HAT structure
of the type pixeltype (see here
for Fortran90, and/or here for the C-version).
The Library allows for a wide variety of the pixelization schemes. The acceptable
pixelization needs to fulfill the following assumptions
(mostly derived from the needs of the efficiency for the transforms themselves).
- the pixelization needs to be isolatitudinal, i.e., the pixel centers have to be aligned with the constant
latitude lines.
- the pixels at the same latitude have to have the same sky area;
- the centers of the pixels at the same latitude have to be equidistant;
- the pixelization has to be symmetric with respect to the equator (though it may have or not
an equatorial row).
No other constraints are imposed.
In addition the library includes a selection of pre-defined pixelizations. As of now those are:
For those pixelization the pixeltype structure can be defined with help of the provided routine, set_pixelization
(here for Fortran90 and/or here
for the C-version).
For all the others the fields of the structure need to be defined by the user.
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