CURVAL
Name
CURVAL
Purpose
Cursor controlled display of image intensities and astronomical coords
Explanation
CURVAL displays different information depending whether the user
supplied an image array, and/or a FITS header array
Note that in the usual truecolor mode, the byte intensity returned by
CURVAL does not correspond to the byte scaled image value but rather
returns the maximum value in each color gun.
CALLING SEQUENCE(S):
curval ;Display x,y and byte intensity (inten)
curval, im ;Display x,y,inten, and also pixel value (from image array)
curval, hdr, [ im, OFFSET= , ZOOM=, FILENAME=, ALT=]
Optional Inputs
Hdr = FITS Header array
Im = Array containing values that are displayed. Any type.
Optional Keyword Inputs
ALT - single character 'A' through 'Z' or ' ' specifying an alternate
astrometry system present in the FITS header. The default is
to use the primary astrometry or ALT = ' '. If /ALT is set,
then this is equivalent to ALT = 'A'. See Section 3.3 of
Greisen & Calabretta (2002, A&A, 395, 1061) for information about
alternate astrometry keywords.
OFFSET - 2 element vector giving the location of the image pixel (0,0)
on the window display. OFFSET can be positive (e.g if the
image is centered in a larger window) or negative (e.g. if the
only the central region of an image much larger than the window
is being displayed.
Default value is [0,0], or no offset.
ZOOM - Scalar specifying the magnification of the window with respect
to the image variable. Use, for example, if image has been
REBINed before display.
FILENAME = name of file to where CURVAL data can be saved.
Data will only be saved if left or center mouse button
are pressed.
Outputs
None.
Side Effects
X and Y values, etc., of the pixel under the cursor are constantly
displayed.
Pressing left or center mouse button prints a line of output, and
starts a new line.
Pressing right mouse button exits the procedure.
If the keyword FILENAME is defined, the date and time, and a heading
will be printed in the file before the data.
Procedures Called
ADSTRING(), EXTAST, GSSSXYAD, RADEC, SXPAR(), UNZOOM_XY, XY2AD
Revision History
Written, K. Rhode, STX May 1990
Added keyword FILENAME D. Alexander June 1991
Don't write to Journal file W. Landsman March 1993
Use astrometry structure W. Landsman Feb 1994
Modified for Mac IDL I. Freedman April 1994
Allow for zoomed or offset image W. Landsman Mar 1996
Proper rounding of zoomed pixel values W. Landsman/R. Hurt Dec. 1997
Remove unneeded calls to obsolete !ERR W. Landsman December 2000
Replace remaining !ERR calls with !MOUSE.BUTTON W. Landsman Jan 2001
Allow for non-celestial (e.g. Galactic) coordinates W. Landsman Apr 2003
Work if RA/Dec reversed in CTYPE keyword W. Landsman Feb. 2004
Always call UNZOOM_XY for MOUSSE compatibility W. Landsman Sep. 2004
Added ALT keyword W. Landsman October 2004
Always test if offset/zoom supplied W. Landsman Feb 2008