Google Earth Community: IGN Géoportail in 3D with Google Earth

Hello,
I am posting to tell about a small software I made, called GEopochi, which brings the IGN Géoportail data into GE (version 4 and above only), by acting as a proxy between the 2. All French territories can be visualized.

Here is what the software does:
* It generates the hierarchy of KML files on demand: These tell GE when to switch to higher precision tiles and the extent of these tiles
* When a request for an image comes, it computes what tiles have to be downloaded from the Géoportail, downloads them if they are not found in the cache, mosaics them, reprojects the mosaic to WGS84 lat/lon, which is the coordinate reference system understood by GE, crops them to the requested extent and sends them back to GE

The requests are handled by a Ruby-on-Rails application and all the raster manipulations are performed through GDAL. Additionnally, some reprojection computations inside the Ruby code are handled by the Proj4 library. Since there is some native code used, it is currently available only on Windows, even though I don’t think there is anything that should prevent it from being ported to Mac OS X or Linux, the source code being open and distributed under the MIT license.

Now about the speed. Frankly, it runs like a hog! That being said, my computer is quite old so it is probably part of the problem and if you don’t move too fast then it is ok... Also, since the software is simply a web application, it can seat on a dedicated machine.

Here is what you have to do in order to make the GEopochi app run:
* Download the Ruby Installer for Windows
* Download Google Earth 4 beta (it won't work on previous versions, I think)
* Download the GEopochi archive and unzip it somewhere convenient. Open the GEopochi folder then double click on launch_geopochi.bat. Doing this should open a DOS-style window with the text Starting Mongrel listening at 0.0.0.0:3000 or something close at the top. This means GEopochi is ready to listen! Then double click on the file called GEopochi.kml, that will open Google Earth and load the list of territories to visit. You can choose places to visit by selecting them in the GEopochi menu.

* To close the app, just close the DOS-style window and wait that all the processing has been terminated.

guilhem
--
The Pochi Superstar Mega Show
guilhem.vellut@gmail.com

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