[iaufwg] Call for vote on the new FITS Standard

[William Thompson]

Dick Shaw wrote:
> While it may be possible to find ways to improve the wording still 
> further in the 3.0 draft, IMHO the time for that has come and gone, save 
> for serious technical flaws. In any case, the suggested change is not 
> correct in the general case: the index in question, j, runs from 1 to 
> WCSAXES.

I believe this is a very serious technical flaw.  If it's not corrected, I would 
have to vote No on the document.

The values of j run from 1 to WCSAXES, but I was talking about the values of 
CRPIXj.  My added sentence was taken verbatim from version 2.1b of the standard, 
so the definition of the standard is not changed in any way.

Steve Allen's suggestion to add wording about pixel centers does not, in my 
opinion, rise to the level of the a serious technical flaw.  However, I would 
not vote against adding such language, if it were well expressed.

> On Tue, 06 May 2008 18:03:44 -0400
>  William Thompson <William.T.Thompson at nasa.gov> wrote:
>> I have done a final reading of the draft FITS standard preparatory to 
>> voting on it.  I am ready to vote in favor of this draft, except for 
>> one small omission having to do with the definition of the keyword 
>> CRPIXj.  Nowhere does it state that CRPIXj runs from 1 to N, instead 
>> of from 0 to N-1.  I've found that the distinction between these two 
>> cases trips up many novice FITS users, and is the most common mistake 
>> made.
>>
>> I suggest the following revised wording, incorporating some of the 
>> wording from version 2.1b:
>>
>> CRPIXj - [fl oating-point; indexed; default: 0.0]
>> Coordinate of the reference point along the pixel axis j.  This value is
>> based upon a counter that runs from 1 to NAXISj with an increment of 1 
>> per pixel.  Note that the reference point may lie outside the image.
>>
>> One might also want to add the phrase "as is the case for the default 
>> value", or something like it, to the last sentence, since 0.0 is just 
>> outside the image.
>>
>> Bill Thompson
>>
>> P.S.  There is an extraneous "the" in the first sentence of section 
>> 7.3.4 on the TDISPn keyword.
> 

-- 
William Thompson
NASA Goddard Space Flight Center
Code 671
Greenbelt, MD  20771
USA

301-286-2040
William.T.Thompson at nasa.gov

(Note changed email address)