[mapserver-users] XML mapfile?

[Steve Lime]

Ok, you're a whiner. <g>

This is being looked into. There are other competing priorities at the
moment so it's down
the list a bit right now. My plan would be to support both native and
XML-based configuration
in the short term until some of the performance issues could be dealt
with. One could actually
make MapServer read XML with just a few tweaks of the lexer, and since
you wouldn't validate
at that point anyway...

I'd like to see the conversation continue, perhaps off list with a
smaller group. Some practical
demonstrations of the benefits of an XML-based config file might also
help those of us not 
experienced with XML see the light.

Steve

Stephen Lime
Data & Applications Manager

Minnesota DNR
500 Lafayette Road
St. Paul, MN 55155
651-297-2937

>>> "C F" <gis_consultant at hotmail.com> 05/22/02 10:51AM >>>
I hear you on the performance concerns.  However, I think we could get

around that by serializing the XML DOM object into a file (that's how
ArcIMS 
does it.... which probably hurts my case more than anything).  Then the
only 
time the XML file would be parsed is in the first request after a
change to 
it is made (done by using file's timestamps).  Who knows, it might even
be 
fast than the current implementation.  I don't really know if that's
true as 
I have not actually used serialized DOM files in my own apps... but it
makes 
sense to me that it could possibly alleviate your performance
concerns.
Now, assuming that performance wasn't an issue, I still hear concerns
about 
simplicity.  In raw text-edit mode, there's nothing that can be done
about 
that.  I consider it a very minor difference... but that's just a
matter of 
taste and there will never be a consensus on that.  All I can say about
that 
is that XML would make it tremendously easier for people to write
mapfile 
generation/editing tools.... also for people writing tools to batch
update 
their mapfiles, etc.  In other words, with maybe the very minor
exception of 
manual text editing, it would make them much easier to handle.... again
a 
maybe matter of taste :)
MapScript is a solution... but may not be a solution for everyone if
they 
want to build a more of a single, cross-platform solution with minimum

modification and customization to the servers involved.  Also, the fact
that 
we'd gain access to this important mapfile information without the need
for 
"programming" would be nice.  I envision this would be set up in much
the 
same way it is now, only with XSLT templates replacing the current form
of 
templates.

Well those are my thoughts.... but I haven't really received any
positive 
feedback since my original post so it looks I'm all alone :)  People
seem to 
be comfortable with the current format.  Or maybe I'm just looking at
it for 
use in different uses than it has traditionally been used for.  I think

everybody that's worked on it has done an *awesome* job.  I think the 
product is great, just call me a whiner if you'd like :)  Paul Ramsey's
idea 
of out we could have it both ways is something I might do for myself
anyway. 
  If there is ever enough interest in it maybe that's somewhere I can 
contribute to the project.



>From: Daniel Morissette <morissette at dmsolutions.ca>
>To: C F <gis_consultant at hotmail.com>
>CC: mapserver-users at lists.gis.umn.edu 
>Subject: Re: [mapserver-users] XML mapfile?
>Date: Wed, 22 May 2002 08:19:31 -0400
>
>I think that Steve has been considering a switch to XML eventually,
but
>I don't think there is any formal plan.
>
>I agree that XML might give more flexibility to the user by allowing
him
>to read the mapfile from external tools, but it would be at the cost
of
>performance (i.e. speed) when parsing the mapfile for every request.
>Combine this loss of performance with the fact that XML would be
harder
>to edit manually than the current format, and you know where I stand
>personally.
>
>I'm not saying that if we were redesigning from scratch I wouldn't
>consider XML (we use it a lot in other apps), but since we've already
>got a very good (fast and simple) mapfile format then I won't be the
one
>initiating a switch to XML mapfiles.
>
>Note that MapScript already gives you access to almost every piece of
>information from the mapfile, so when the CGI cannot do what you need
>then the logic path is to switch to MapScript, and then sky is the
>limit.
>
>My 0.02$
>--
>------------------------------------------------------------
>  Daniel Morissette               morissette at dmsolutions.ca 
>  DM Solutions Group              http://www.dmsolutions.ca/ 
>------------------------------------------------------------
>   Don't put for tomorrow what you can do today, because if
>       you enjoy it today you can do it again tomorrow.






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