[OSGeo-Standards] Re: [tiling] OGC Tiled WMS Discussion Paper

Sophia Parafina sophia.parafina at ionicenterprise.com
Thu Sep 13 12:57:16 EDT 2007

I heard back from Carl Reed and he says that it will be available after
the Technical Committee meeting on Sept. 20th.


Edric Keighan wrote:
> Keith,
> FYI ...
> How our proposal fits with OpenLayers recommendations referenced at 
> the following site: 
> http://wiki.osgeo.org/index.php/WMS_Tiling_Client_Recommendation
> Regards,
> Edric
> Sophia Parafina wrote:
>> I've asked Carl Reed at OGC to make it available for comment.
>> sophia
>> Christopher Schmidt wrote:
>>> On Fri, Sep 07, 2007 at 10:47:27AM -0400, Frank Warmerdam wrote:
>>>> Folks,
>>>> I was contacted by Edric Keighan about a discussion paper that was
>>>> recently submitted to OGC (with Cubewerx as the editor) titled:
>>>>    07-057r2 OpenGIS Tiled WMS Discussion Paper
>>> I'm guessing this would be a continuation of OGC 07-057? The editors of
>>> that were not Cubewerx, but from uab.cat, if my records serve. I'd be
>>> interested in seeing either of the two documents, and would ask that  
>>>> I believe it is roughly comparible in goals to this work:
>>>>    http://wiki.osgeo.org/index.php/WMS_Tile_Caching
>>>> I believe Edric is interested in feedback on the paper and support 
>>>> for the
>>>> proposal (for those of us who are OGC members) and perhaps more 
>>>> importantly
>>>> he is interested in implementations of the specification within our 
>>>> projects
>>>> with OpenLayers being the most obvious candidate.
>>> OpenLayers is unlikely to add support for further tiled WMS
>>> specifications through the work of its current set of developers.
>>> Additional layers would need to be created, tested, and supported by
>>> some other person who would accept 'ownership' of the layer type: I've
>>> already avoided including some functionality in OpenLayers simply
>>> because no one was willing to take on the task of supporting it.
>>> If some person or organization is willing to take on the task of
>>> supporting a layer, then in general, OpenLayers is open to the task of
>>> adding that functionality. However, I'm somewhat hesitant to include
>>> yet-another way of accessing pre-cached WMS information: especially if
>>> it has not taken into account the design goals of the Recommendation we
>>> created at the last FOSS4G, which is described at:
>>>   http://wiki.osgeo.org/index.php/WMS_Tiling_Client_Recommendation
>>> An example of things we explicitly discussed and discarded:  * 
>>> GetTile requests -- we wanted to stick with GetMap, and simply allow
>>>    for matching the map request to a tile when appropriate.
>>>  * Using anything other than the standard GetCapabilities for 
>>> describing    functionality: GetCapabilities allows for vendor 
>>> extensions, and this
>>>    seemed the right way to pass the information back to the client
>>>  * Starting the tiles at the '0,0' point of the world  (Instead 
>>> choosing    to go for the lower left corner). Note that this is 
>>> different from
>>>    Google's tiles, but the same as WorldWind's.  * Creating any new 
>>> form of requests -- it's easiest for client
>>>    functionality to simply extend the existing requests rather than
>>>    creating new formats.
>>> Again, I don't know what's in the document: if someone could tell me
>>> more specifically how to get a copy of it, I could offer a more formal
>>> review from the point of view of an implementor of a tile map server.
>>> Thanks for the heads up, Frank.
>>> Regards,

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