[mapserver-users] XML mapfile?

[Mike Haarman]

CF,

You are not alone.  I've had similar discussions off-list with Steve and
Daniel.  There is no consensus yet, but developments at OGC point in
this direction also.  This is neither here nor there, but I would like to
address the two concerns raised here.

Performance.  I really feel this is a non-starter.  Your solution is one
method and there are others for optimization of XML parsing.  Its not
trivial work, but it is perfectly feasible.

Editing.  XML is self-documenting, human-readable, plain-text as we all
know.  Where is the difficulty?

Your points about generation and transformation are right on,
particularly in light of the opportunities for integration with other
publishing or content delivery environments.

Mike

On Wed, 22 May 2002, C F wrote:

> 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.
>
>
>
>
>
>
> _________________________________________________________________
> MSN Photos is the easiest way to share and print your photos:
> http://photos.msn.com/support/worldwide.aspx
>
>

----------------------------------------------------------------
Mike Haarman                        Minnesota Population Center,
mhaarma at socsci.umn.edu              University of Minnesota,
                                    537 Heller Hall,
                                    Minneapolis, MN 55455
Co-Architect, Programmer,
  National Historical GIS -- http://www.nhgis.org/
Maintainer,
  DDI Codebook DTD -- http://www.icpsr.umich.edu/DDI/