- NAME
TICS
- PURPOSE
Compute a nice increment between tic marks for astronomical images.
- EXPLANATION
For use in labelling a displayed image with right ascension
or declination axes. An approximate distance between tic
marks is input, and a new value is computed such that the
distance between tic marks is in simple increments of the
tic label values.
- CALLING SEQUENCE
tics, radec_min, radec_max, numx, ticsize, incr, [ /RA ]
- INPUTS
radec_min - minimum axis value (degrees)
radec_max - maximum axis value (degrees)
numx - number of pixels in x direction
- INPUT/OUTPUT
ticsize - distance between tic marks (pixels)
- OUTPUTS
incr - incremental value for tic labels (in minutes of
time for R.A., minutes of arc for dec.)
- REVISON HISTORY
written by B. Pfarr, 4/14/87
Added some more tick precision (i.e. 1 & 2 seconds in case:) EWD May92
Added sub arcsecond tick precision W. Landsman May 2000
Plate scale off by 1 pixel W. Landsman July 2004