A Space & astronomy forum. SpaceBanter.com

Go Back   Home » SpaceBanter.com forum » Astronomy and Astrophysics » FITS
Site Map Home Authors List Search Today's Posts Mark Forums Read Web Partners

[fitsbits] question about WCS keywords for pixel list



 
 
Thread Tools Display Modes
  #1  
Old September 4th 09, 04:12 PM posted to sci.astro.fits
Phil Hodge
external usenet poster
 
Posts: 5
Default [fitsbits] question about WCS keywords for pixel list

According to Table 2 in WCS Paper I, all the keywords for the pixel list
representation of an image include the table column number as part of
the keyword name. This description agrees with the example in Table 10
of WCS Paper II. It seems to me, however, that several of these
keywords should include the world coordinate axis number rather than the
column number. I checked the "unofficial errata" for Papers I and II
but didn't find any mention of this.

Consider the case of a time-tag table containing columns TIME, X, and Y,
which are respectively the time when a photon was detected and the pixel
coordinates in a 2-D image where it was detected. To use a specific
example, suppose the world coordinates are right ascension and
declination. The reference pixel keywords are TCRPX2 and TCRPX3, giving
the column numbers of the X and Y columns. But shouldn't the keywords
for the world coordinates at the reference pixel be TCRVL1 and TCRVL2
rather than TCRVL2 and TCRVL3 (and similarly for several other
keywords)? The WCS papers say the latter keywords are the ones to use,
but it would be more consistent with the keywords for an image in the
primary array if the former keywords were used.

Phil
 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
[fitsbits] Repeated header keywords (was: Proposed Changes tothe FITS Standard) Dick Shaw FITS 1 August 20th 07 08:46 AM
[fitsbits] Sample pixel list files William Pence FITS 0 October 11th 06 09:38 PM
[fitsbits] Sample pixel list files William Thompson FITS 0 October 11th 06 08:27 PM
[fitsbits] which WCS keywords? Phil Hodge FITS 5 September 19th 05 01:55 AM
[fitsbits] Blank strings in FITS keywords. Tom McGlynn FITS 4 March 1st 05 07:27 PM


All times are GMT +1. The time now is 07:46 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 SpaceBanter.com.
The comments are property of their posters.