[gdal-dev] gdal2tiles strangeness

[Mano Marks]

Hi Klokan,

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?

Mano

2009/3/31 Klokan Petr Přidal <klokan at klokan.cz>:
> 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 <mmarks at google.com> 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.
>> mmarks at google.com
>> http://twitter.com/ManoMarks
>> _______________________________________________
>> gdal-dev mailing list
>> gdal-dev at lists.osgeo.org
>> 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.
mmarks at google.com
http://twitter.com/ManoMarks