Re: [Zmapserver-developers] Re: New directions for ZMapServer

[Sean G. <sgi...@fr...>]

Hi Michael,

Do you follow bike racing?  When is Ullrich going to turn it on?
And why did he leave Telekom?  It seems like Bianchi is not so
strong.

OK, back to the web and maps :)  I am going to weave my response
into yours below:

On Friday, July 4, 2003, at 08:04  AM, Michael Schulz wrote:

> Dear Sean,
>
> thank you very much for the ZmapServer presentation, that as far as i
> could see from your slides, looks really interesting and also puts the
> ZmapServer Product in its appropriate position.
>
> I have read your mail over and over again and your ideas sound very
> promising. I agree with you, that in order for ZmapServer to be a
> competitive player in the MapServer Interfacing League (like MapLab or
> so) the OGC WMS compatibility is crucial.
>
> I think your idea of creating a WMS class that would act like Zope DA 
> is
> great and also goes in a similar direction like the data layer object
> seperate from the zmap instance that you thought of a while ago.
> Implementing this to work with zmap instances would be a good step in
> separating data administration, map administration and web layout 
> tasks.
>

I am starting to get serious about the WMS adapter classes this week.
This could be really exciting, because it will make it possbile for
Zope programmers to begin to access WMS services for map content
without having to know anything about MapServer!  The WMS adapters
will behave as much as possible like a ZMap instance so that site
developers can treat them identically.  To begin, this means that
a WMS adapter instance will have a draw() method.

> It seems to me that in your proposal you stress very much the OGC WMS
> Client features (i.e. connecting to distant WMS servers, using their
> data, etc.). But i think also very relevant are the features of a
> ZmapServer (?) / WMS server class that has WMS serving capabilities, in
> order for distant servers to include your own WMS layers and to be able
> to provide cascading WMS capabilities.

ZMapServer 0.7 is a OGC WMS 1.1.1 server.  The next few (0.7.2+)
releases will add some backwards compatibility to earlier WMS
versions.  Is there any chance you'd be willing to delete the
stuff you have on www.zopecms.de:446/map_test and replace it
with the stuff from zmapserver 0.7.1?

> To come back to the Zmap/Zsession classes. I think it important to have
> a fully functional zmap interface, that is, being able to provide the
> complete map instance editing capabilities over the ZMI, thus through
> the web (with all the Zope security and roles management stuff these 
> are
> features that other mapping TTW interfaces or CMSs hardly can provide).
> If this is achieved we would already have thorough WMS serving
> capabilities. I think you are right, that the ZmapSession Object is
> already at a reasonible functional level.
>
>> From this point it would be really good if we can specialize certain
> features and seperate them to form individual classes with individual
> functionality.
>
> Perhaps we should think of working simultaneously in three branches
> (more crosses more important at the moment in my opinion):
> - zmap instances development +++
> - zmapSession development    +
> - WMS instance development   ++
>
> Ok, that's my 2 ct.
>
> Cheers, Michael
>

I think the three areas of development would be:

- zmap instances including WMS server
- WMS adapter instances
- zmap session

The client area will be my focus for the near future.

I'd also love to discuss how we might change the session framework
so that it incorporates the WMS adapter.  What do you think about
reducing the scope of our session framework so that the session
only holds map extent?  Currently, keeping a MapScript mapObj
in the session data manager results in memory leaks.  We could
cut down or eliminate the leaks by simply storing extents in the
session data.

Hope all is going well in Freiburg.  June was cool and wet in
Colorado, but now summer has arrived.  It is consistently 35+
every day and no measureable rain in almost two weeks!

cheers,
Sean


--
Sean Gillies
sgillies at frii dot com
http://www.frii.com/~sgillies