id	summary	reporter	owner	description	type	status	priority	milestone	component	version	severity	resolution	keywords	cc
116	Coordinate Transformations	gusciora@…	Paul Price	"The SDRS states that the functions:
    psSphereTransformICRStoEcliptic(void)
    psSphereTransformEcliptictoICRS(void)
    psSphereTransformICRStoGalatic(void)
    psSphereTransformGalatictoICRS(void)
simply create a sperical transform struct and set the appropiate values.
The ADD states that these functions shall wrap various SLALIB functions.
However, the specified SLALIB function map a specific point in one coordinate
system to a specific point in another coordinate system.  They do not
provide the parameters of that coordinate transform.  Can you clarify how we
are to implement the above functions using those SLALIB functions?

Section 5.3.3 of the SDRD specifies a list of ""projection types"".  The
following projection types are not defined in the ADD:
    PS_PROJ_PAR
    PS_PROJ_GLS

During a previous polycon, it was decided that angles shall be in radians,
not degrees.  However, the the formulas for the various projections in
section 1.2.3 of the ADD assume angles are in degrees.

Can you specify an algorithm for psSphereTransformApply()?

psSphereSetOffset() and psSphereGetOffset(): the explanation ""A linear
offset is defined to be a linear offset in a tanget projection centered on
the starting coordinate with y axis aligned with the local direction or
increasing Declination"" is unintelligible to me.  The psuedo-code in the ADD
does not seem quite right, but I don't understand the topic well enough to
be sure.  It seems to me that the offset should be added to the position,
somehow.  However, I don't see that this is being done.  I've implemented
the psuedo-code almost exactly.  Can you verify that this is correct?  Also,
what does the following mean ""the given offsets must the scaled based on the
given offset units"".

Can you help us with test points for these functions?  Without the
astronomical background to know what the different coordinate systems are, I
can't really tell if my implementations are correct."	defect	closed	high		PSLib SDRS	unspecified	normal	fixed	IPP-doc