100% correct answer, thanks!
That's exactly what I was looking for.
Gdal has great resampling algoritms, but with certain files, it's better
to 'photoshop' the overviews in order to get maximum quality. And with
certain server software, like Geoserver, you can't use external
overviews. I could also imagine that some one would want to use
different overviews than those derived from the original. I know there
are several technichs for achieving the same effect, but this is one
way, especially if you want to separate it from the code.
thank you very much,
- mika -
11.8.2011 20:55, Even Rouault kirjoitti:
Le jeudi 11 août 2011 17:56:33, Lehtonen, Mika a écrit :
Hi,
sorry for asking something without googling it more beforehands, but I
believe my questions are so trivial that someone can answer to them
right away.
I believe, with latest gdal versions you can "swap" GeoTiff internal
overviews or by other words, use for example your own tiffs as internal
overviews. Am I right?
I'm not 100% sure to understand your question/need, but here's my
understanding anyway
Let's suppose you have a TIFF, foo.tif
You want to use a custom overview (perhaps not based directly from foo.tif,
could be a scan of another map at the same extent but at another scale). You
call it foo.tif.ovr
Then GDAL will see foo.tif.ovr as an overview of foo.tif
You want to package a new file with the main image containing the imagery of
foo.tif and the overview containing the imagery of foo.tif.ovr
You will use GDAL>= 1.8.0 and do :
gdal_translate foo.tif bar.tif -co COPY_SRC_OVERVIEWS=YES
See http://gdal.org/frmt_gtiff.html
From which version has this been possible?
Syntax for the proper option (gdal_translate or/and gdalwarp?)
reg. mika
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