iraf.net

NUMBER:	485
MODULE:	longslit.fitcoords
SYSTEM:	-V2.11.3b
DATE:	Mon Jun  4 11:43:22 MST 2001
FROM:	valdes

BUG:    The user coordinates from IDENTIFY are double precision and
	are written to the database with 9 digits of precision.  FITCOORDS
	reads and uses this data in real precision.  The deletion point
	file with the user coordinates of the delete points is written in
	real precision.  The comparison between the coordinates written to
	the deletion list and later read again and the data read from the
	IDENTIFY database is done as a direct comparison of two real
	values.  Because of how the conversion and rounding between text
	and floating point representations are done this can result in
	deleted points which are in the deletion file to not be restored as
	deleted in subsequent runs of FITCOORDS.  There is no easy
	workaround.  The only possiblity is to match the values in the
	deletion file with the IDENTIFY database file and make the ascii
	representation be the same.  Working in units which require fewer
	significant digits to represent the coordinates may improve the
	behavior.  For example when working in the IR use microns instead
	of Angstroms in IDENTIFY/REIDENTIFY.

STATUS:	The direct equality will be replaced by a tolerance comparison in
	a future release.