Wednesday, June 11, 2008

X my L

Uh oh, the most unkillable meme in the OSGeo firmament is back, the XML map file. Even more unkillable than the "rasters in PostGIS" meme, the XML map file waits out the winters under the thick bark of .Net and Java programmers and blossoms every six months or so, until knocked back by the harsh frost of having-to-do-it-yourself and a Skeptical Development Community.

Me? I'm all for it. Check out my shopping list for today.

For me, it's all about human readability.


James Fee said...

You might want to depreciate tomatoes these days.

Bill said...

If it were me, type and quantity would be attributes rather than tags but you say tomato... :)

xanadont said...

Can you transform this into RSS, please? I want to subscribe to your food feed.

Allan Doyle said...

Is that valid GML? Where's the CRS?

Regina Obe said...

I guess I'm the only one that thinks XML is overrated. Sure XML is easier to validate but who cares. I write perfect map files that don't need any validation.

Rasters in PostGIS though. Think of the possibilities Paul. Not just satellite but useful analytical stuff with DEMs etc.

Paul Ramsey said...

I think you missed my smiley face, Regina. :)

Tom said...

Paul, where's the schema? :)

I think the MapServer mapfile was put forth before the days of XML, and probably would have been XML-based if it had been defined post 2001-ish.

I love the current mapfile format, in terms of creating it by hand. When it comes to programmatic access, I think XML (and the wide range of tools/parsers out there) would better serve a mapfile definition.

If we were to indeed come up with an XML-based mapfile, the possibility of cross-project interoperability becomes appealing. Having said this, there is a fine line in defining a format based on consensus, and allowing enough extensibility without allowing too much "fairy dust" (one of my favourite terms, from Rob Atkinson, 2003), which something like xs:any potentially provides.

Here's a neat link which discusses XML and when to use:

In the end, I think the most important thing is consensus in the community.

..Tom (who still prototypes XML schemas by hand)

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