KML is the markup language used to add geographic features and metadata to Google Earth. KML is short for “Keyhole Markup Language,” Keyhole being the company behind the original version of Google Earth, acquired October 2004. KML is an XML grammar, which means it is processed in the same as HTML and XML files are processed by a web browser. Google announced an update to KML today as one of many updates in the geospatial line.
New KML features include:
Smart Streaming: There is now level-of-detail behavior that allows the KML creator to fine-tune how data is presented in Google Earth. Called “regions” in the KML documentation, this feature allows streaming of large datasets and smoother viewing. This is similar to remote viewing products in the CAD marketplace that offer streaming of visual datasets across a network. Viewing can begin before the entire file arrives, and the level of detail improves as the streaming continues. Before this change, large datasets had to be completely loaded onto the user’s computer before viewing could begin. It was an all-or-nothing situation which sometimes overloaded the system. The ability to stream also means that the creators of KML files can serve the data to Google Earth users, instead of having users download the KML file to their local computer before viewing.
Textures and COLLADA: 3D objects can be modeled with realism in a CAD or other graphics environment in their correct coordinate space and then imported into Google Earth and placed on the Earth’s surface using KML. When a 3D model is imported into Google Earth, it is translated, rotated, and scaled to fit into the Earth coordinate system. Until now the model data could not include textures, bit-mapped images that overlay a model to provide photorealism. KML 2.1 adds the ability to import 3D models with textures, using the COLLADA interchange file format. This format was created by Sony for importing 3D data into PlayStation 3 and PlayStation Portable games. The format is now controlled by an industry consortium that includes Google and Apple as members.
Incremental updates: KML data previously loaded into Google Earth can be updated, changed, or deleted.
Expiration: KML creators can specify a data refresh rate, so that information on display stays current. This will allow KML files to deliver real-time information such as changing weather patterns, real-time flight details, transit and traffic updates, bird migrations, and updated reports on anything else that moves.
--RSN
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