Call for comments -RFC 39
Yewondwossen Assefa
yassefa at DMSOLUTIONS.CA
Thu Nov 15 12:11:44 EST 2007
Steve,
Stephen Woodbridge wrote:
> Yewondwossen Assefa wrote:
>> Hi all,
>>
>> I have put together an RFC outlining changes that could be done to be
>> able to support Named styles in WMS/SLD. I would appreciate your
>> comments on it:
>>
>> http://mapserver.gis.umn.edu/development/rfc/ms-rfc-39
>>
>> Thanks
>>
>
> Assefa,
>
> Thank you for a well written RFC. I have a couple of questions/comments.
>
> When I think of "NamedStyles", I think of a section of the mapfile that
> just has a bunch of STYLE blocks, that can be reused anywhere by
> referencing there names. This make the STYLE object reusable via the
> name reference. Also redefining a STYLE only needs to be done in one
> place not N places, which greatly simplifies the mapfile maintenance.
>
> The advantage of this is that it modularizes the mapfile and compresses
> it greatly. It would be great to define a 13/11 red/white casement road
> STYLE and then reference it multiple times in my mapfile via its name
> for example.
>
> Your proposal instead moves us in the opposite direction of adding more
> text tags to the layers and making them more verbose and less
> comprehensible.
>
> Was thought given to anything similar to my description about? What
> other implementations were considered and rejected? Why? if any.
>
> Would the above idea be compatible with WMS/SLD issues you are trying to
> solve or could it be adapted to this problem?
>
I agree with you (and Bart who made the same remarks), that have a
representation table (RST) at some higher level and being able to access
the "styles" by name in the layer would be a great addition. We could
have something similar to what we do with symbol files and attach the
RST to a map file. I used the term NamedStyles in the RFC since that is
what is used in the SLD specifications and I understand that outside the
SLD world it's interpretation could lead to a confusion.
But I think, I am not addressing the RST support in this RFC, at least
not intentionally :)
I also think that even if we had this RST concept in MapServer, I
would still need to find a way to define/publish several mutually
exclusive styles on a layer. The mechanism proposed I think could well
be applied even if Mapserver implements an RST
> What are the levels of effort of these two implementations?
>
I did not estimate really what It would take to implement and RST in
Mapserver although this idea has been floating around for a long time.
It would be interesting to see in details how this would be implemented.
I am convinced that it could be a good addition to Mapserver.
Thnaks
> Thanks,
> -Steve W
>
--
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Assefa Yewondwossen
Software Analyst
Email: assefa at dmsolutions.ca
http://www.dmsolutions.ca/
Phone: (613) 565-5056 (ext 14)
Fax: (613) 565-0925
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