[georss] Use GeoRSS in web feeds that provide earthquake information

[Joshua Lieberman]

Franklin,

Thanks for your hard work and concern about "correct" application of  
GeoRSS. Clearly we need better explanations and many more examples of  
various uses for these properties. The basic principle we tried to  
follow is for georss to take care of the both fundamental and generic  
feature properties, first a geometric representation for it, and  
second a delineation of what sort of feature is being described.

We specifically have left out other attributes which may characterize  
a particular feature type because this is such a wide open field. It  
may in the future be of interest to include a fixed attribute element  
in the style of the GML profile BXFS:

Example:
  <georss:what>
   <georss:featureproperty>
        <georss:propertyname>noaa:seismicMagnitude</georss:propertyname>
       <georss:propertyvalue>7.1</georss:propertyvalue>
   </georss:featureproperty>
</georss:what>

This isn't even on the roadmap yet, however, let alone part of the  
present GeoRSS spec.

Others, such as Peter Vretanos at Cubewerx, have been encoding  
feature properties as XHTML (e.g. tables) in the atom:content element  
of their feeds, which makes them able to pop up nicely in many viewers.

As for the present feature tags: they are intended for describing  
more closely the identity of the reported feature and how the  
geometry represents it, e.g.

<georss:point>37.3 136.5</georss:point>
<georss:elev>-50000</georss:elev>
<georss:featuretypetag>Earthquake</georss:featuretypetag>
<georss:relationshiptag>HypocenterOf</georss:relationshiptag>
<georss:featurename>pacific.2007.03.25.010535</georss:featurename>

There is of course no police authority to prevent anyone from using  
the GeoRSS tags for other purposes, but that comes with the risk that  
only one's immediate group will understand what those purposes are,  
and therefore the feeds will be of little interest / utility in the  
wider world.

GeoRSS has not to this point included any other location  
representations than geometry under its namespace. Partly this is  
because there are already other namespaces which can cover either  
addresses (xCal) or placenames (geonames). The GeoRSS "team" still  
has the need to  describe and illustrate better how this should be  
done, as well as come to a more explicit decision whether small  
profiles of these standards should be "adopted" into a future GeoRSS  
version.

Cheers,

Josh

Joshua Lieberman, Ph.D.
Principal, Traverse Technologies Inc.
mailto:jlieberman at traversetechnologies.com
tel +1 (617) 395-7766
fax: +1 (815) 717-981


On Apr 4, 2007, at 10:02 AM, Franklin Tse wrote:

> Hi,
>
> The Pacific Tsunami Warning Center (PTWC) is using GeoRSS in their  
> feeds[1]. Currently, magnitude information is contained in the  
> georss:radius elements, which is clearly an abuse according to the  
> specification. I have reported the issue to the webmaster of PTWC,  
> Mr. Brian Shiro, and he replied:
>
> "I know the <georss:radius> tag was not meant for magnitude, but it  
> seemed the best choice from available namespaces. We are already  
> using the <georss:featurename> tag for the name of the region where  
> the earthquake occurred. If you have another suggestion for a  
> possible magnitude tag, we would be interested in hearing it."
>
> I read the specification again and again, and I think the following  
> elements may be used.
>
> (For the item with guid pacific.2007.03.25.010535)
>
> <georss:point>37.3 136.5</georss:point>
> <georss:elev>-50000</georss:elev>
> <georss:featuretypetag>Hypocenter</georss:featuretypetag>
> <georss:relationshiptag>Magnitude</georss:relationshiptag>
> <georss:featurename>7.1</georss:featurename>
>
> Is my example correct and usable?
>
> If yes, the remaining question is, where should "NEAR WEST COAST OF  
> HONSHU  JAPAN" be placed? Should PTWC remove that info?
>
> Regards,
> Franklin Tse
>
> References:
> 1. http://www.prh.noaa.gov/ptwc/feeds/ptwc_rss_pacific.xml
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