[gdal-dev] PDF-->JPEG-->KML. Confused about association between KML bounding box and PDF's neatline and corner coordinates.

[Even Rouault]

You don't need to convince anyone to add new functionnality. It already exists
;-)

See the -cutline option of gdalwarp. Basically you use the NEATLINE reported by
gdalinfo as the CUTLINE (that was the sole purpose of reporting the NEATLINE by
the way !)

The easiest way is to make a simple CSV like this :

foo,WKT
bla,"POLYGON((....))"

and you paste the content of NEATLINE as the value of the WKT.

and do a gdalwarp without reprojecting to crop (use -crop_to_cutline) to the
neatline. Then you can do a 2nd gdalwarp to reproject to the target SRS.

(if you want to do just one gdalwarp, you'll have to do ogr2ogr to reproject the
cutline.csv into the target SRS)

See http://gdal.org/gdalwarp.html and/or
http://gdal.org/structGDALWarpOptions.html#0ed77f9917bb96c7a9aabd73d4d06e08


> Boris,
>
>    Use gdalwarp to convert your jpeg to Geographic coordinates (I think
> it needs to be converted for KML anyways):
>
> gdalwarp -t_srs EPSG:4326 in.jpg out.jpg
>
> then use gdalinfo to get the corner coordinates.
>
> Currently the entire page of the PDF is rendered into the image.
> Perhaps we can convince Even to add an option to convert only the mapped
> area (or mask everything else?)
>
> Best Regards,
> Brent Fraser
>
> On 10/20/2010 8:07 AM, Boris Dev wrote:
> > My objective is to make a KML ground overlay with a geospatial PDF map.
> >
> > Using GDAL's translate utility I have converted the PDF to a JPEG. The
> > next step and problem for me is to write the text of the KML ground
> > overlay, which requires a text of bounding box information like this:
> >
> > <LatLonBox>
> >          <north>37.91904192681665</north>
> >          <south>37.46543388598137</south>
> >          <east>15.35832653742206</east>
> >          <west>14.60128369746704</west>
> >
> >
> >          <rotation>-0.1556640799496235</rotation>
> >        </LatLonBox>
> >
> > As GDAL's output, I saw that the entire PDF with legend, title, etc
> > and not just the map image was converted.
> >
> > As GDAL's output, I also saw 2 parts of data that seem they are useful
> > to match a bounding box to the map within the jpeg, but I cant figure
> > out the puzzle of how to make this work? Can I get the bounding box of
> > the entire PDF image with this information below?
> >
> > Corner Coordinates:
> > Upper Left  (  666937.758, 2024687.983)
> > Lower Left  (  666991.811, 2018338.153)
> > Upper Right (  674511.276, 2024754.795)
> > Lower Right (  674565.328, 2018404.965)
> > Center      (  670751.543, 2021546.474)
> >
> > <MDI key="NEATLINE">POLYGON ((672676.488065659650601
> > 2019417.955749646294862,672636.091432046378031
> > 2024030.267778463661671,667347.405745737953112
> > 2023983.612156898481771,667385.539170471020043
> > 2019370.524140953086317,672676.488065659650601
> > 2019417.955749646294862,672676.488065659650601
> > 2019417.955749646294862,672676.488065659650601
> > 2019417.955749646294862,672676.488065659650601
> > 2019417.955749646294862))</MDI>
> >
> > I realize the coordinate above need to be converted to lat/long to be
> > a KML ground overlay onto Google Maps, which I think I can handle.
> >
> > But I am unsure if I need to extract the map image from the jpeg using
> > the NEATLINE?
> > How are the Corner Coordinates translated into a bounding box?
> >
> > Any suggestions?
> >
> >
> > _______________________________________________
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> > http://lists.osgeo.org/mailman/listinfo/gdal-dev
>