[georss] Multiple geometries in simple?

[Josh@oklieb]

Torsten,

You have an interesting and useful application of GeoRSS, but it does  
lead to a few questions, which I've commented on below.

Cheers,

Josh


Joshua Lieberman
mailto:josh at oklieb.net
tel +1 (617) 395-7766
fax: +1 (815) 717-981


On Jan 9, 2007, at 4:01 PM, noiv wrote:

>> In general I agree with Mikel and Ron, that GeoRSS Simple was
>> designed for a single geometry, and you should probably play in the
>> GeoRSS GML space if you're doing something more complex.
>
> I tuned my wordpress blog to generate GeoRSS instead of RSS
> and while focussing earth related topics I easily run into the  
> question
> of multiple geometries.
>
> Example:
> http://exploreourpla.net/global-warming/blog/heat-wave-in-europe- 
> and-united-states.html
>
> Feed:
> http://exploreourpla.net/feed/

A couple of observations:

1) The examples in GeoRSS 1.0 are unfortunately wrong, and the extra  
tags such as featuretypetag are meant to occur at the same level as  
georss:where, not inside of them.

2) A string such as "DE - Bremerhafen, AIW" is a featurename, not a  
featuretype

3) The "semantic" of GeoRSS is that it turns a resource such as an  
article into a feature. Your feed extracts the geometries for two  
different features (e.g. North Sea and the Wegner Institute) and  
refers to the same article. This leads to ambiguity in what the feed  
communicates, and how to represent it. Should a viewer turn those  
into two different entries pointing at the same article? Should it  
come up with different symbols which indicate they are different  
features in the same entry? Mostly when we have discussed allowing  
multiple geometries, it has been in the context of different  
representations (e.g. a point at one scale, a polygon at another  
scale) for the same feature.
>
> A planned application will use a full export of all articles
> as GeoRSS and display all these geoLinks/geometries
> linked to the content on a clickable 'map of climate change'.

My suggestion for being clearer and helping viewers out would be to  
create multiple entries referencing the same article, each defining  
one feature and associated geometry. Clicks could go to the same  
reference but roll-overs could provide the distinct featurename for  
each symbol.

>
> But I'm not sure about correct XML - is there any validator available
> capabable of proving right use of featuretypetag and multiples in  
> GeoRSS GML?

No, there isn't any way with XML Schema to limit the number of times  
an entry like georss:where occurs in an RSS entry, but the 1.0 georss  
schema does limit the contents of georss:where to a single geometry  
(e.g. gml:Point). < Note to list: the schema links in 1.0 seem to be  
broken, but the schemas are at http://www.georss.org/xml/1.0 >

featuretypetag takes a qualified name, which suggests but doesn't  
require that the namespace be represented by a register which could  
be used for validation.

>
> And I disagree, turning a relation from 1 to N does not exactly lead
> to more complexity. A programmer implementing a parser should
> be able to write a simple loop and handle this situation.

It may be less the complexity of coding something and more the  
complexity of interpreting the results of the code.

>
> But wether GML or not, it is quite useful to have a standard which  
> easily
> links textual content and geographic maps in both directions.
>
> Torsten Becker - ExploreOurPla.net
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