It's the imagery, stupid

The reasons we're using KML (which some consider a fork of an early version of GML) instead of GML (version 3) for "GeoWeb" applications have almost nothing to do with the actual merits of these formats. It all comes down to imagery, imagery, imagery. If only there was as much semi-free, global, high-res imagery behind GML 3 applications as has been deployed for Google Earth, we'd all be deliriously in love with GML. Stefan Geens and Frank Taylor would be tirelessly blogging about all the awesome possibilities of GML. Google would have indexed half a billion GML documents. I might even write a Python GML library. People aren't doing things with KML that you couldn't do with GML. It's all about the free-ish imagery on the KML platform.

(with apologies to James Carville)


Re: It's the data, stupid

Author: Paul Ramsey

Same thing holds for the GMaps APIs and Google Earth as a piece of software. The truly innovative thing Google did was not the technology it was (just as in their search business) the business model shift: from direct payment for data to free data with indirect payment via advertising. That their software was pretty cool was icing on the cake, but it was all that free(ish) data that won the day.

Re: It's the imagery, stupid

Author: Matt Giger

It's sad how the geospatial community is so beholden to Google, who can yank the "free maps" rug out from under anyone at any time.

Re: It's the imagery, stupid

Author: Ron Lake

I think it was a convergence of multiple factors - the fact of global data (especially images) - the wars in Iraq on CNN - the realization by Google that people wanted to see themselves and tell stories - and a good execution on the side of the Earth Browser and use of KML for control and visualization.

Since GML has a very different intent, I don't think we would be focused on billions of GML files. GML was never intended for visualization nor browser control (as in "look here") - so is not intended for end users. It is more intended for under the hood plumbing - communicating between databases - transporting eospatial transactions and the like. I think GML has expanded in a number of domains from climate science to city modeling to commercial aviation and even into the bed rock (IETF) of the Internet itself. I don't think its play is over by any means - maybe just at the start. GML and KML play complementary roles and if one wants a GeoWeb that is more "web like", understanding on building on that complementarity is even more important.

Author: Ron Lake

Actually I would not agree with this statement. While one could have written KML in GML (and not the other way around) - that would still be an abberration of the intent of GML. GML is intended to capture geospatial content quite apart from HOW it is presented. KML is all about presentation and browser control. KML is not very useful where we are mainly concerned with machine to machine communication. GML is not all that useful in communication with people. True there was a component called default styling and some good innovations around things like "topology styling" this was never central to GML.

Re: It's the imagery, stupid

Author: Matt Priour

In the same vein, I would really like to see Google Maps API (which the others will follow) read GeoJSON data directly. I know it is an almost trivial javascript processing task to translate those into Google Map features, but having native support would greatly boost the "importance" of that format.

As it is now, clients that want to generate dynamic maps in Google Map have a strong preference for KML or GeoRSS. GeoRSS as a format is a mess since one can use any combination of one of the RSS syndication protocols (RSS 1.0, RSS 2.0, Atom) combined with one of the geometric representations formats. At least Google Maps shows a preference for Atom with GML for GeoRSS but any XML based format can be parsed and used.

Re: It's the imagery, stupid

Author: Eric Wolf

Maybe I'm just a paleo at heart - but I find it more startling that almost all of this imagery is in a Mercator projection (Euro-centric, global north land sizes enlarged, global south diminished, Poles fail). Sure, if you're trying to sail from Spain to Florida, it's a damned good projection. But there aren't many other redeeming qualities.

The GeoWeb is constantly imposing de facto standards that those of us labelled paleo cringe over.

Re: It's the imagery, stupid

Author: Ian Painter

More and more people assume that the GeoWeb is something that only lives in the browser, I don't agree with this and Ron has a point. People 'dis' GML for being too complex for the browser, but its not really designed for that. Whilst B2C is clearly all about the browser, B2B isn't going to happen there and GML is more popular than ever for B2B data exchange. Yes KML solves the 80/20 but don't underestimate how important that 20% can be. In my mind to get 100% GeoWeb you need 80% B2C and 20% B2B. That's KML, GML, REST and SOAP living in harmony.

Re: It's the imagery, stupid

Author: Brian Hamlin - darkblue_b

well, it *is* the imagery, and more ! Twenty-five years ago, a mouse was a specialized instrument, and I recall vividly the PC crowd bemoaning "graphics" as a productivity killer.. User interface, accessibility, ease of adoption, utility, ubiquity and transferability of skills and work product all play a part in the adoption of new technology.

At the

5th International Symposium on Digital Earth

(my first) two years ago, I realized that Geo Browsers was something whose time had come, on a number of levels. I have no qualms about representing KML to the old-timers - and I have gotten some suspicious stares here and there.. but listen to this - its not that I fear our future with computers, at this point I fear our future *without* computers. (apologies to Isaac Asimov)

Re: It's the imagery, stupid

Author: Terry Stigers

@Eric Wolf: Thanks. From one caveman to another.