[CAP] Geospatial Elements

[Bob Bunge]

And in that spirit, more to consider:

Here's an email from Dave Doyle, senior NGS geodesist.

Key sentences:
Organizations like FAA (and unfortunately ICAO), WMO and IHO  have often 
recommended a global reference frame and they usually cite WGS 84 
because of their lack of geodetic experience.
It needs to be recognized that WGS 84 is defined strictly for the U.S. 
GPS and is not the coordinate system used by other space-based 
positioning systems such as the Russian GLONASS, which uses PZ-90 
(Parametri Zemli 1990, Parameters of the Earth 1990) or the EU Galileo 
which will use the Galileo Terrestrial Reference Frame.

The International Association of Geodesy (IAG) recommendation is ITRF. 
Unfortunately WGS 84 is often cited because it's the best known.

Art Botterell wrote:
> Let's remember, though, that CAP is an international standard.  Anything that looks like an attempt to impose US-local standards will, if previous experience is any guide, be resisted with considerable vigor.
> 
> -Art
>   
> -----Original Message----- 
> From: Arnie Shore <3ashore at comcast.net> 
> Cc:  <cap-list at lists.incident.com> 
> To: Bunge, Bob <Robert.Bunge at noaa.gov> 
>  
> Sent: 11/5/2007 8:38:44 AM 
> Subject: Re: [CAP] Geospatial Elements 
>  
> At the risk of introducing still more complexity into the lat/long  
> discussion, I'll note that there's a shift to the The National Geodetic  
> Reference System (*NGRS*).  Information at  
> http://www.ngs.noaa.gov/PUBS_LIB/develop_NSRS.html 
>  
> Arnold Shore 
> Annapolis, MD 
>  
> Bob Bunge wrote: 
>> NOAA's National Weather Service (and I assume most other US Govt  
>> agencies) is starting to standardize to the current US Federal standards  
>> of the North American Datum of 1983 (NAD83) for horizontal positioning  
>> and the North American Vertical Datum of 1988 (NAVD88) for elevation  
>> values, which  together are known as the National Spatial Reference  
>> System (NSRS). 
>>
>> NOAA s National Geodetic Survey (NGS) is the federal agency responsible  
>> for the specification and maintenance of the NSRS. 
>>
>> Is this a need?  I'm not a geospatial datum expert (I'm told there isn't  
>> that much difference between the two and other uncertainties are likely  
>> much larger when it comes to horizontal products like tornado warnings)  
>> so I can't say for sure at this time. 
>>
>> Bob Bunge 
>> NWS 
>>
>> Mick Jagger wrote: 
>>    
>>> Hi, 
>>> 	A number of posts have mentioned changing CAP's geospatial elements to use GML.  I think a clarification needs to be made about whether the posters are talking about full-monty GML, or a custom CAP profile akin to Simple.  To me the question boils down to whether different Coordinate Reference Systems need to be available to CAP.  Anybody have a need for something other than WGS84? 
>>>      
>> ___ 
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