Fwd: [emergency] Groups - Updated CAP 1.1 issues

[Art Botterell <acb@incident.com>]

[Sent this to Carl direct when I meant to copy the list...]

Begin forwarded message:
> From: Art Botterell <acb@incident.com>
> Date: June 15, 2005 9:50:25 AM PDT
> To: Carl Reed <creed@opengeospatial.org>
> Subject: Re: [emergency] Groups - Updated CAP 1.1 issues
>
>
> Carl -
>
> OK, I'll add that to the issues list.
>
> Personally... and I don't have any more votes than anyone else on  
> this TC... I'm still not sure this is really necessary.  The one  
> Australian implementer I know of didn't report any problem with  
> WGS-84.
>
> Anyway, I think we're all agreed that we need to standardize on  
> *something*, lest every receiving device be burdened with providing  
> a full library of CRS conversions.  (Whether WGS-84 is the best, or  
> at least the least-bad, choice is something we can revisit, of  
> course.)
>
> And once that standard representation is present, anyone can  
> convert it to and from any local framework they like, so including  
> it in the CAP message seems merely redundant.  (And of course, if  
> its really that important to a particular sender, a GML document  
> with whatever more detailed and various information is desired can  
> always be attached as a <resource>.)
>
> I think this may be another case where we should resist the  
> temptation to try to be everything to everybody... both to avoid  
> bloat and to keep the "standard" from becoming merely a coat of  
> interoperability-colored paint slapped on what remains a tangle of  
> stovepipes.
>
> - Art
>
>
> On Jun 15, 2005, at 6/15/05 8:30 AM, Carl Reed wrote:
>
>> Art -
>>
>> Not to open a can of works (again), but below is a comment from a  
>> highly
>> respected geospatial/IT expert in Australia. The comment is WRT  
>> use of WGS
>> 84. While this comment was made in the context of some ongoing OGC
>> standards work, I believe that it is germane to the work of this  
>> TC - both
>> CAP and EDXL. Personally, I would like to see CAP as widely  
>> adopted as
>> possible in the international community. I am therefore suggesting  
>> that we
>> enhance CAP 1.1 (?) to allow specification of other coordinate  
>> reference
>> systems. This could be done by references. I have proposed this  
>> numerous
>> times. Perhaps now is the time to consider adding an optional  
>> element to
>> CAP to allow specification of a CRS other than WGS 84.
>> Cheers
>>
>> Carl
>>
>> The other contentful issue I would beg to differ on is the Annex B
>> directive that WFS servers *must* support WGS84 "to enable
>> interoperability across regional boundaries".Whatever you North  
>> Americans may like to think, jurisdictions in the rest
>> of the world really do *not* keep all their data in WGS84 - for  
>> example,
>> much Australian data is still stored in AGD84 (which makes it  
>> ~200m offset
>> from WS84) and even for those jurisdictions that have updated to  
>> GDA94
>> there is an offset of ~2m which is small but still enough to cause
>> problems with utilities.And either AGD84 or GDA94 is legally  
>> mandated.Cross-regional interoperability can only be ensured by a  
>> coordinate
>> transformation service.Whatever the North American-based vendors  
>> would
>> like to think, you just can't mandate global compliance to WGS84.
>>
>>
>>
>>
>>
>
>