[georss] Quick Fire Summary

Allan Doyle adoyle at eogeo.org
Mon Apr 30 12:47:06 EDT 2007


On Apr 30, 2007, at 12:41, Carl Reed OGC Account wrote:

> Hi Allan -
>
> I that actually WMS 1.1.1 is by far the most widely implemented  
> version of WMS.

Right. Thanks. Too many "3"'s flying around...

>
> Cheers
>
> Carl
>
> ----- Original Message ----- From: "Allan Doyle" <adoyle at eogeo.org>
> To: <georss at lists.eogeo.org>
> Sent: Monday, April 30, 2007 10:18 AM
> Subject: Re: [georss] Quick Fire Summary
>
>
>>
>> On Apr 30, 2007, at 12:02, Peter Borissow wrote:
>>
>>> The CRS discussion has been alittle difficult to follow and someone
>>> definately needs to clarify the axis order question. Specifically:
>>>
>>> Is GeoRSS Simple lat/long or long/lat?
>>
>> GeoRSS Simple is lat/long
>>
>>>
>>> Is EPSG 4326 lat/long or long/lat? I'd love to see a specific
>>> reference document/spec that clarifies this!
>>
>> EPSG 4326 is lat/long.
>>
>> The history of the confusion stems from ca. 1999 when the OGC WMS
>> spec was defined to use EPSG codes for the CRS but the bbox values
>> were defined as decimal degrees in long/lat order.
>>
>> This was fine for a while until the EPSG purists at OGC realized what
>> was happening so WMS 1.3 actually changes the order for EPSG:4326.
>>
>> That caused another uproar and there's now a new code that you're
>> supposed to use when you want WGS84 with decimal degrees in lon/lat
>> order.
>>
>> However, the EPSG:4326 genie is out of the bottle. There was little
>> interest at OGC in a compromise that said "do the math according to
>> the EPSG values, but let the WMS representation be long/lat".
>>
>> This is one reason why WMS 1.1.3 is the most popular version.
>>
>> Allan
>>
>>>
>>>
>>> Thanks,
>>> Peter
>>>
>>>
>>> ----- Original Message ----
>>> From: Carl Reed OGC Account <creed at opengeospatial.org>
>>> To: georss at lists.eogeo.org; Christopher Schmidt
>>> <crschmidt at metacarta.com>
>>> Sent: Monday, April 30, 2007 10:34:42 AM
>>> Subject: Re: [georss] Quick Fire Summary
>>>
>>>
>>> Chris -
>>>
>>> Thanks for the notes on the meeting. Checked out the new drupal
>>> based site.
>>> No problems, although some of the colors used for headings are a
>>> bit washed
>>> out.
>>>
>>> On another topic, I happened to read more closely the section on
>>> CRS. Don't
>>> ask me why - perhaps because in the OGC right now there is a major
>>> discussion and new member collaboration on defining a common
>>> coordinate
>>> model.
>>>
>>> Anyway, the paragraph on CRS is a bit confusing and perhaps
>>> misleading. I
>>> know that we want to keep discussions on such topics as CRS a
>>> simple as
>>> possible. So perhaps a bit of rewording and some references might
>>> be in
>>> order. I am happy to take this on and provide the text for
>>> consideration.
>>>
>>> Finally, what is GeoRSS NS? - not simple :-)
>>>
>>> Thanks
>>>
>>> Carl
>>>
>>> ----- Original Message -----
>>> From: "Christopher Schmidt" <crschmidt at metacarta.com>
>>> To: <georss at lists.eogeo.org>
>>> Sent: Friday, April 27, 2007 6:21 PM
>>> Subject: [georss] Quick Fire Summary
>>>
>>>
>>>> Quickfire summary of discussion during GeoRSS meeting. (I'm  
>>>> slightly
>>>> inebrietaed, so anything you have questions about, please reply
>>>> rather
>>>> than assume the worst):
>>>>
>>>> * The GeoRSS Drupal website is ready to go. On Monday, we will  
>>>> switch
>>>>   the site to the Drupal site. If you have problems with the drupal
>>>>   site ( http://georss.org/drupal/ ) speak this weekend to get them
>>>>   fixed.
>>>>
>>>> * GeoRSS NS is simple geometry description for the web of content.
>>>>   This means that it can be used in much more than RSS. However,  
>>>> it's
>>>>   not 'feature description' -- its not GML. It's not meeting the
>>>> needs
>>>>   of people who need complex feature description -- it's a  
>>>> framework
>>>>   for simple description of web content. (Despite what was said
>>>> earlier
>>>>   on the list, GML is *not* the de facto simple encoding of Geo
>>>> Data on
>>>>   the web, nor will it be, due to its reliance on XML Schema and  
>>>> its
>>>>   relative complexity compared to GeoRSS Simple.)
>>>>
>>>> * GeoRSS GML uses gml properties in the reverse way that every  
>>>> other
>>>>   GML example on the web seems to use them. (i've been using  
>>>> lots of
>>>>   WFS servers via OpenLayers, and they always spit out x,y, not  
>>>> y,x).
>>>>   As a result of this, we should make it VERY CLEAR on all pages  
>>>> that
>>>>   we are using y,x. This probably means that we should add examples
>>>>   that are in places like new zealand, and hawaii: well outside the
>>>>   comfortable -90 -> 90 box where there can be confusion.
>>>>
>>>> * georss:when should be proposed, if people want it. However, in
>>>>   general, GML properties are at best not recommended, and at worst
>>>>   actively discouraged, in favor of two alternatives:
>>>>
>>>>     * Encoding GML information inside alternative existing
>>>>       atom-friendly namespaces
>>>>
>>>>     * Creating a "gml feature" property into which a full GML  
>>>> feature
>>>>       can be added -- so, if you need to transport GML information
>>>> with
>>>>       your GeoRSS feed, you may want to create/propose a
>>>> georss:feature
>>>>       property, which then lets you refer to a full GML Feature,
>>>>       including 'time', full gml geometry, etc.
>>>>
>>>> * Styling via KML should probably be a 'best practice'
>>>> recommendation,
>>>>   but probably not a 'part of GeoRSS' -- something to be  
>>>> described by
>>>>   example, since it applies equally to all RSS, rather than  
>>>> something
>>>>   that is a normative part of a spec. (The alternatives here are
>>>>   basically KML / SLD -- SLD seems likely to be too complex, and
>>>> lacks
>>>>   the built in remote-refrence semantics that the KML styling
>>>> mechanism
>>>>   has -- at least to the knowledge of the participants in the conf
>>>>   call.)
>>>>
>>>> * Visualization of GeoRSS in *feed readers* -- that is, making  
>>>> clear
>>>>   to the general world that creating a georss feed has value to
>>>>   feed consumers, rather than just producers and gis consumers.
>>>>   Bloglines, NetNewsWire, even Firefox should *do something with  
>>>> the
>>>>   geo* -- the lack of geo support puts geo producers in a crappy
>>>>   situation.
>>>>     * Mime type doesn't help this. There are no applications to  
>>>> pass
>>>>       the mime type off to. Once there are, then it makes sense to
>>>>       re-discuss the mime type issue.
>>>>
>>>> In general:
>>>>
>>>> * GeoRSS Simple is Simple Feature definition for the content-based
>>>> web.
>>>> * GeoRSS GML is a small set of extension (georss:where) wrapped
>>>> around
>>>>   GML geometry.
>>>> * Extending GeoRSS should be secondary to well-documented fully
>>>>   exampled current-spec driven code with implementations. There
>>>> are far
>>>>   more importan things to think about than tweaking the spec to
>>>> include
>>>>   some niche use case.
>>>> * GeoRSS needs to get RSS readers to understand Geo. This is the
>>>> single
>>>>   thing that most limits adoption -- no feedreaders with Geo  
>>>> support
>>>>   means no incentive to publish geo in RSS.
>>>> * Styling is cool. Needed for some cases, not for most.
>>>> * GeoRSS uses a simple feature encoding that is good for lots of
>>>> things
>>>>   that aren't RSS. Accentuate that via examples and prose.
>>>>
>>>> I think that's the essence of our conversation. Again, this isn't a
>>>> smoke-filled room: arguments welcome :)
>>>>
>>>> -- 
>>>> Christopher Schmidt
>>>> Boy Genius, MetaCarta
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>>>
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>>
>> -- 
>> Allan Doyle
>> +1.781.433.2695
>> adoyle at eogeo.org
>>
>>
>>
>> _______________________________________________
>> georss mailing list
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>> http://lists.eogeo.org/mailman/listinfo/georss
>

-- 
Allan Doyle
+1.781.433.2695
adoyle at eogeo.org






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