Google recently open sourced a new 3D compression library called Draco. The new library promises high compression rates for 3D graphics and promises much faster page loads for web pages with 3D graphics.
It was apparently the Chrome Media team that developed the library, but we are wondering whether or not the Google Maps and Google Earth teams have taken note. Both Google Earth and Google Maps in ‘Earth’ mode would benefit significantly from better compression. We do not know what compression methodologies they currently use, or how they compare to this new library.
Google Earth benefits from having a cache, but as we found out when investigating how much data 3D imagery requires, the cache is actually quite small relative to the amount of 3D data available and unless your internet connection is blazingly fast, you will spend most of your time in Google Earth waiting for imagery to download and this is especially true for areas with 3D imagery. Better compression would not just speed up downloads, but also effectively boost the size of the cache – assuming the imagery is stored in the cache in compressed format.
Do any of our readers know what compression Google Earth and Google Maps currently use for 3D imagery?
The compression format for KML files is the standard ZIP format (when saved as KMZ).
2D imagery
Google Earth image overlays support .jpg and .png. When it comes to standard 2D satellite and aerial imagery, we do not know what it uses internally or what format is used to transfer imagery from the servers, but given that the Google Earth client has not seen any major version updates for years, our guess is that it is using rather out-dated compression. Google has put a lot of effort into 2D image compression formats, such as WebP, and Google Earth would probably benefit from those too.