sexagesimal

[Alberto Conti]

On Sep 17, 2006, at 11:58 AM, Roy Williams wrote:

> Alberto Conti wrote:
>>
>> The adoption of a well known ISO standard or specification seems  
>> the most appropriate thing to do, instead of coming up with yet  
>> another IVOA recommendation that is just a poor compromise.
>
> Alberto:
>
> (1) I have tried to find existing standards, but ISO seems to have  
> nothing. The word "sexagesimal" in Google does not show a  
> recommended notation that I could find. Other information is from  
> "people like us" (Iraf, Starlink, Vizier, etc) and recommends  
> various output formats. In other words, I don't think there is a  
> Sexg standard representation.
>
this is true, but what you could do is look at "time standards" from  
ISO (8601? I think) and extend them to IVOA standards.

> (2) The IVOA is a standards organization. Our job is to make  
> standards. Obviously, our standards should not be poor.
>
perhaps poor was a bad choice of words. My concern is that we propose  
something disjoint from what the users are using at the moment (see  
FITS) and will be using. I do agree that some standardization is  
indeed require...
Supporting all these format
     Decimal Degrees
185.63325 29.8959861111111

Hours, minutes and Seconds
12 22 31.98      29 53 45.55
12h22m31.98s     29d53m45.55s
12:22:31.98     +29:53:45.55
12h22'31.98"     29d53'45.55"
12h 22m 31.98s   29d 53m 45.55s
12h 22' 31.98"   29d 53' 45.55"
12h 22' 31.98"  -29d 53' 45.55"
12h22'31".98    -29d53'45".55
12h22m31s.98    -29o53m45s.55
12h 22' 31".98  -29d 53' 45".55

Hours/Degrees and Minutes (no seconds)
12 22     29 53
12h22m   +29d53m
12h22m    29d53m
12:22m    29:53m
12h22'    29d53'
12h 22m   29d 53m
12h 22'   29d 53'
12h 22'  -29d 53'


like MAST and most archives do is rather impractical.

> (3) I suggest that many formats be "acceptable" to IVOA  
> applications with wide inclusivity. If that effort works, perhaps  
> we can think of a tighter format that is "recommended".
>
indeed, you should accept input in various formats, but you must  
recommend one from the IVOA.

> (4) Part of the effort here is to allow our customers to put  
> multiple things in text boxes. If it parses to 2 floats, we assume  
> long/lat in degrees, if it parses to six numbers, it is Sexg, or  
> else perhaps it is an object name.
>
again, perhaps the focus should be to get a clear understanding from  
users (archive searches for example?) on the most common format(s)  
and then move to the definition of an IVOA standard.
Just my $.02

-A


>
> California Institute of Technology
> 626 395 3670
>

___________________________________________________
Alberto Conti, Ph.D.
Chief Engineer
Space Telescope Science Institute (STScI)
3700 San Martin Drive, Baltimore MD 21218
Tel: 410-338-4534   Fax: 410-338-1592