Hi Klokan, Thanks for all your help on this. The steps you outlined are very similar to what I tried originally. Even with the new gdal2tiles.py, and following your instructions exactly, I get the same result. When I open the doc.kml it looks great. But when you zoom out, the tiles shift to what I believe are projected images.
Adding -p geodetic does fix the problem, but it would be nice to figure out if this is a bug and then fix it. Mano 2009/4/3 Klokan Petr Přidal <[email protected]>: > Dear Mano, > > You are right, gdal2tiles.py in stable GDAL 1.6 has a bug for KML > generation in "-p raster", which is now fixed in gdal-trunk as well as > in maptiler SVN... > > Here is it step by step for your process: > > - Download the latest gdal2tiles from gdal-trunk or maptiler svn and > save it on your disk: > http://maptiler.googlecode.com/svn/trunk/maptiler/gdal2tiles.py > > - Download the "world.200401.3x21600x10800.jpg" (or any other world map): > http://earthobservatory.nasa.gov/Features/BlueMarble/BlueMarble_monthlies.php > > - Assign georeference and srs: > gdal_translate -of vrt -a_srs epsg:4326 -a_ullr -180 90 180 -90 > world.200401.3x21600x10800.jpg world.vrt > > - Create 'raster' tiles (it will automatically generate KML, because > input is epsg:4326): > python ./gdal2tiles.py -p raster world.vrt > > Open doc.kml in Google Earth... ;-) > > If you don't want to update the gdal2tiles utility and you need > workflow with stable GDAL 1.6 then use: > > gdal2tiles -p geodetic world.vrt > > It will generate you correct KML for Google Earth directly and viewer > compatible with OpenLayers base map and other WMS, WMS-C, and TMS > services, but your map will be resampled to one of the fixed map > scales - according the TMS Global Geodetic profile definition: > http://wiki.osgeo.org/wiki/Tile_Map_Service_Specification > > Best regards, > > Klokan > > 2009/4/3 Mano Marks <[email protected]>: >> So, using -p "raster" creates far worse distortion in the KML. I'm back to >> not using it. I get distortion only at the highest zoom levels that way. >> >> 2009/4/1 Klokan Petr Přidal <[email protected]> >>> >>> Mano, >>> >>> > Thanks for the pointer. So it looks like, right now, there's a bug in >>> > gdal2tiles, according to Jesse? Any news on when that might be fixed? >>> >>> Just use this gdal2tiles.py: >>> http://maptiler.googlecode.com/svn/trunk/maptiler/gdal2tiles.py >>> >>> The issue he is referring is fixed in MapTiler SVN: >>> http://code.google.com/p/maptiler/issues/detail?id=9 >>> Commited in maptiler SVN in r17 on Mar 20, 2009. >>> >>> I am proposing to fix all known bugs during this summer as part of >>> Google Summer of Code project, and also implement support for OGC WMTS >>> standard, publish a stable version of MapTiler >>> (http://www.maptiler.org/) and synchronize the code with GDAL SVN. >>> >>> Klokan >>> >>> > >>> > Mano >>> > >>> > 2009/3/31 Klokan Petr Přidal <[email protected]>: >>> >> Mano, >>> >> >>> >> If you would like to have both Google Maps and Google Earth >>> >> presentation for a global map then you must generate two tile sets, >>> >> because Google Maps supports only Mercator tiles (EPSG:900913) and >>> >> Google Earth only geodetic (EPSG:4326). >>> >> >>> >> GDAL2Tiles has as a default tile profile 'mercator', it means that it >>> >> will warp your input into Spherical Mercator internally. >>> >> To create tiles and KML for Google Earth for your EPSG:4326 input data >>> >> you should use -p "raster". >>> >> >>> >> From the "gdal2tiles --help": >>> >> >>> >> -k, --force-kml Generate KML for Google Earth - default for >>> >> 'geodetic' >>> >> profile and 'raster' in EPSG:4326. For a dataset >>> >> with >>> >> different projection use with caution! >>> >> >>> >> Detailed description of recommended step by step usage of gdal2tiles >>> >> for global maps was posted by Jesse Varner >>> >> from CIRES & NOAA/NGDC, who used gdal2tiles for official presentation >>> >> of Global magnetic anomaly map EMAG2 (for Google Maps/Earth) at: >>> >> http://ngdc.noaa.gov/geomag/data/Google_Maps/EMAG2/index.html >>> >> >>> >> His post is here: >>> >> http://groups.google.com/group/maptiler/msg/fe105e27a62711e4 >>> >> >>> >> Best regards, >>> >> >>> >> Klokan >>> >> >>> >> On Tue, Mar 31, 2009 at 6:37 PM, Mano Marks <[email protected]> wrote: >>> >>> I'm getting started with gdal2tiles, and I'm getting strange results. >>> >>> >>> >>> I downloaded a blue marble jpg from NASA: >>> >>> http://www.nasa.gov/vision/earth/features/blue_marble.html >>> >>> >>> >>> And I ran the following command lines: >>> >>> >>> >>> gdal_translate -of VRT -a_srs EPSG:4326 -gcp 0 0 -180 90 -gcp 21600 0 >>> >>> 180 90 -gcp 21600 10800 180 -90 world_200401.jpg bluemarble1.vrt >>> >>> >>> >>> gdalwarp -of VRT -t_srs EPSG:4326 bluemarble1.vrt bluemarble2.vrt >>> >>> >>> >>> gdal2tiles -k bluemarble2.vrt >>> >>> >>> >>> Of course, the last step took awhile. >>> >>> >>> >>> The Google Maps and OpenLayers output was fine. However, the KML had >>> >>> some odd results. When loaded directly, it looked fine, but when I >>> >>> zoomed out, it appeared that what was the equivalent of zoom 0 and 1 >>> >>> the images retain a Mercator projection. Is this a known issue, or did >>> >>> I do something wrong? >>> >>> >>> >>> -- >>> >>> Mano Marks >>> >>> Geo Developer Advocate >>> >>> Google, Inc. >>> >>> [email protected] >>> >>> http://twitter.com/ManoMarks >>> >>> _______________________________________________ >>> >>> gdal-dev mailing list >>> >>> [email protected] >>> >>> http://lists.osgeo.org/mailman/listinfo/gdal-dev >>> >>> >>> >> >>> >> >>> >> >>> >> -- >>> >> http://blog.klokan.cz/ >>> >> http://www.maptiler.org/ >>> >> http://www.oldmapsonline.org/ >>> >> >>> > >>> > >>> > >>> > -- >>> > Mano Marks >>> > Geo Developer Advocate >>> > Google, Inc. >>> > [email protected] >>> > http://twitter.com/ManoMarks >>> > >>> >>> >>> >>> -- >>> http://blog.klokan.cz/ >>> http://www.maptiler.org/ >>> http://www.oldmapsonline.org/ >> >> >> >> -- >> Mano Marks >> Geo Developer Advocate >> http://twitter.com/ManoMarks >> Join me for Google I/O, Google's biggest Developer Conference, in San >> Francisco, May 27th and 28th, 2009 >> http://code.google.com/events/io/ >> >> > -- > http://blog.klokan.cz/ > http://www.maptiler.org/ > http://www.oldmapsonline.org/ > -- Mano Marks Geo Developer Advocate http://twitter.com/ManoMarks Join me for Google I/O, Google's biggest Developer Conference, in San Francisco, May 27th and 28th, 2009 http://code.google.com/events/io/ _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
