[gdal-dev] Re: Gdal2tiles in Gdal18 and creating KMZ files

[Roland Duhaime]

I have been working with the png creation option under "gdal_translate -of
kmlsuperoverlay" to create kmz files that include transparency.  I haven't
had much luck with controlling specific colors that becomes transparent, or
even maintaining transparency in the source HFA file.  The handling of
transparency is different from gdal2tiles, where I have had good results.
This leads me back to gdal2tiles and attempting to create a kmz file from
the tile structure.  The key difference I see between the .kml files using
the two different processes is below.   In order to be able to compress the
gdal2tiles output into one file, I believe that I may need to modify
gdal2tiles.py to create the gx:LatLonQuad tag from section 1 below as
opposed to the LatLonBox from section 2 below.  Does anyone know the
difference between gx:LatLonQuad and LatLonBox before I decide if this
change is appropriate?:

(1) KML Superoverlay snippet:

        <GroundOverlay>
            <drawOrder>0</drawOrder>
            <Icon>
                <href>0.png</href>
            </Icon>
            <gx:LatLonQuad>
                <coordinates>
                    -74.885604, 40.373168, 0
                    -74.269963, 40.373582, 0
                    -74.267506, 41.083329, 0
                    -74.889723, 41.082904, 0
                </coordinates>
            </gx:LatLonQuad>
        </GroundOverlay>

(2)GDAL2Tiles Kml snippet:

        <GroundOverlay>
          <drawOrder>16</drawOrder>
          <Icon>
            <href>159.png</href>
          </Icon>
          <LatLonBox>
            <north>40.97989806962016</north>
            <south>39.90973623453719</south>
            <east>-74.53125000000000</east>
            <west>-75.93750000000000</west>
          </LatLonBox>
        </GroundOverlay>

Thanks Again,
Roland


On Sun, Feb 20, 2011 at 6:12 AM, Vadim Shlyakhov <vadp.devl at gmail.com>wrote:

> brian <rush <at> winkey.org> writes:
>
> > the problem is in /12/1211/2558.kml line 26
> >
> > <href>2558.png</href>
> >
> > this should be a relative path from the root of the zipfile not from
> > 2558.kml
> >
>
> Hello Brian,
>
> I've made another tile cutter (http://code.google.com/p/tilers-tools/). It
> produces a directory tree in a manner which is very similar to
> gdal2tiles.py. So
> I had a look into this problem.
>
> I must say it didn't work for me either: GE shows KML just fine, but if I
> zip a
> dir tree into KMZ it fails altogether. I've tried relative paths to PNGs,
> to
> internal KMLs. All these were to no avail.
>
> I think that the problem actually lies in '<NetworkLink>' things and I
> still
> cannot get a clue on these.
>
> I wonder if you have (or can produce manually) a sample of working KMZ with
> superoverlays, so I'd be able to have a look
>
> _______________________________________________
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> gdal-dev at lists.osgeo.org
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>
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