[Gdal-dev] GeoQuadTree - an open format for storing georeferenced images

Jordi Gilabert Vall jordi at geoquadtree.org
Tue Nov 14 05:25:06 EST 2006


Some time ago I needed the retrieval from very large georeferenced raster
images in a OGC WMS server, and I wanted to avoid the use of tile indexes or
catalogues of images, neither a database. I started thinking of an open
format for storing arbitrarily large georeferenced images. I named this
format "GeoQuadTree", as it would be based on a quadtree of rectangular
tiles, each in PNG format on the filesystem, in a simple hierarchical
structure of folders. I wrote a command line utility for creating it,
importing from PNG/JPEG/TIFF and exporting to PNG/JPEG/TIFF/GDAL. I also
wrote a GDAL driver for this format. I tested successfully with my own WMS
server software, and on MapServer compiled with GDAL support. It worked very
well on Blue Marble Next Generation at a resolution of 15 arc-seconds, i.e.
86400x43200 pixels.

You can find more information on the project web site:


I'm testing the release 1.0.0, you can test it on the subversion repository
if you want (I haven't packaged it yet).

I think it's a useful format, open, very easy to use, and very efficient (in
terms of response time).

Do you think it could be useful for you ? Would you like to include it on
GDAL's next release ?

jordi at geoquadtree org
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