November 13, 2005

GML, and KML - Why the fuss?

Various other blogs have been making comparisons between GML and KML.  Such discourse is interesting, however, I think that most of them miss the point.  Comments like KML is light and GML is heavy -  or "I was like a kid in a candy store" - are misleading at the best and  border on being disingenuous.  The difference, the key difference between GML and KML is not complexity nor expressiveness, and can be expressed in a single word - Google.  Had Google decided to use GML (and THEY DID) - we would be saying the same things about GML as KML.  This is not sour grapes - it is simply reality.  One can easily argue that KML is already a profile of GML - just unoffically so.

Of course you would not want to express avionics in KML, nor the charts for ships at sea.  The point of GML was to enable profiles on which could be constructed application vocabularies for different domains.  The rise of KML reinforces the importance of XML in the geospatial domain and in no way reduces the efficacy or importance of GML.

Posted by RLake at 20:23:48 | Permanent Link | Comments (4) |
Comments
1 - As always, customers (the marketplace) drive the adoption of standards - not standards bodies.

Anyone who has sour grapes at google is forgetting that. Just because standards bodies 'tell' people to use GML does not mean that it will be adopted by customers. Defacto standards have traditionally played a larger role.

Defense Contractor BBN Technologies gave us the @ sign for email, CERN gave us the WWW via the URL and HTTP, NCSA gave us web browsers, Adobe gave us PDF, Autodesk gave us DXF, ESRI gave us SHP etc etc.

TCP/IP arose DESPITE the OSI 'standards' - in fact X.500 is the only OSI standard used today.

J. (Comment this)

Written by: James at 2005/11/13 - 23:10:09
2 - Absolutely - I could not agree more and this was my point. (Comment this)

Written by: Ron Lake at 2005/11/14 - 17:56:32
3 - What''s the discussion really about? KML uses some GML and it is one of GML''s greatest success stories. As one of the few folks that was working on GML in 1999 and 2000 (GML 1) what Keyhole appears to have done was take some of the tags from early GML and integrate into work they were doing under contract to develop KML.

Bottom Line - KML uses GML for some geometry and then adds other stuff and that''s great.

One point that folks seem to be circling around is Google support to standards. It''s true that the marketplace "drives the adoption of standards-not standards bodies". However, is it really in the interest of everyone to have one company control a de facto "standard" representation of the world? For example, if I wanted to change something in KML, how do I do it?

Regards,
Jeff (Comment this)

Written by: ************* at 2005/12/20 - 13:38:28
4 - Both KML and GML are being adopted by the market place, but by different adoption groups. GML is popular in the government, which supports standardisation, while KML is popular among Google Earth users. Google seems to be after the "long tail" of smaller but more plentiful users. KML was designed specifically for use with Google Earth, and it is therefore simpler. GML, in contrast, was designed to be general-purpose. I agree with Ron that the enthusiasm about KML has a lot to do with the availability of a visualisation client and the ease of sharing data. This is not a problem of GML as a language per se. The creation of the OGC-powered Geo-Web may take some time, because it depends on the actions of hundreds of stakeholders. One interesting question is why hasn't any of GIS giants come up with something similar to Google Earth? Is it the lack of creativity or lack of resources? (Comment this)

Written by: Alex Milanovic at 2006/02/05 - 00:48:38
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