RLake, who appears to be one of the developers of the original GML markup language and who blogs at Geo-Web, has written an interesting series comparing KML with GML.

In Part I – Feeding the web with Geographic Information, he wonders why KML is considered revolutionary if GML went down that same road five years ago. He concludes that it is the whole Google Earth package that is revolutionary. I’d add that a markup language for geographic data is obvious, even if it is with hindsight, and that there are only so many ways to mark up geographic data (and one best way, probably).

In Part II – GML and KML, he provides (tongue-half-in-cheek) instructions for making your own Google Earth. It all comes down to how well you style your marked-up data, and Google Earth does this better than most.

Finally, in GML and KML Syntax he compares the two markup languages in terms of their purpose and abilities. There is plenty of interesting stuff on that blog.

3 thoughts on “KML vs. GML”

  1. Just should clarify my position on KML and GML. It is clear that this is NOT a question of GML vs KML. KML is a presentation language – a language for geographic data presentation. It is like W3C SVG except that it draws on the Earth “canvas” rather than just a rectangular region on your screen. GML is not designed as mapping language. It is designed to represent geographic objects – to provide the ability to define a machine readable geospatial vocabulary which can be shared across a community of interest.

    GML can be carried in KML using the KML Metadata tag and it can easily be styled to KML for presentation. This is NOT a question of CONVERTING GML to KML – it is matter of interpreting the geographic content for presentation to human consumers.

  2. I asked a similar question to one of Google Maps&Earth project ex-member, and the answer was very simple: “We’re making the enterprise standards just like Microsoft”.

    I think he is right. If you wait for an approvement of an open standard for years then you will loose the game.

  3. Are Ron Lake’s GML vs KML comparisons available online somewhere else? I checked the links above and they are 404. We are using KML for a project where I work, and my employer wants to know if GML would be a better choice. From my POV they seem fairly equivalent, but there is relatively little comparative information (that I can find) online.


    Scott C. in NC

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