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The Keyhole Markup language (KML) is a means of representing geographic information in a simple XML file making it easy to share map data among different creation and visualization systems. Ever since Google acquired Keyhole in 2004 (the original creators of Google Earth) they have steadily expanded the KML syntax leading up to KML 2.2 which is used widely by dozens of mapping applications today.* This Monday KML became an industry standard approved by the OGC - read the details here on CNET where the news was first released and learn more about KML2.2.

Live Maps first started to support KML last year when we introduced the ability to import KML files into Collections or view KML hosted on the web. This week we released a nice upgrade with improved support for KML including better styling and presentation. In fact, the CNET article uses a screenshot from Live Maps illustrating the effect of global warming on national parks using data from the National Resources Defense Council that was provided in KML format. The KML Overlay is very rich showing the boundaries of the parks along with some text for each. The CNET author comments that the map loads slowly in Live Maps. To compare I loaded the same KML file in Google Maps and it was indeed much quicker (15 seconds and 5 seconds respectively). But then I noticed something interesting - on Google Maps the polygons representing the parks didn't load at all. Live Maps took longer as it was reading, parsing, and displaying the entire KML file. Its nice to see Live Map's KML support coming along as quickly as it is! Our work is definitely not done as we e still have a lot of KML workitems on the backlog ... expect even more improvements and better KML support in our upcoming releases.

Click each screengrab below to view the national parks KML in Live Maps and Google Maps respectively

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and for the hardcore mapping nerds, further discussion of KML 2.2 and its becoming a standard can be found here on Spatially Adjusted. is KML the poor mans GML? or is it a great means of easily sharing Geo Data? enter the fray if you dare... Personally, I'd say both. KML is a great tool for the right job, but depending on the job you may need to expand your toolbox. I like the "KML is to to GML what HTML is to SGML" analogy. My first job as a software developer was at a publisher building document management systems based on SGML. Verbose, complex, unlimited flexibility, perfectly suited for machine maintained data (no one would want to edit an SGML document and its related DTD by hand!) Along came HTML, carelessly slamming content and style together in a single file with limited syntax that was pretty easy to edit with a plain text editor. A nightmare for data management purists, but liberating for the masse. To this day both have their place in this world and their own strengths not shared by the other. HTML's weaknesses have been addressed over time (CSS for instance) and continues to evolve. Are KML and GML any different? I think the parallels are very clear.