Jukka,
Thanks those are great threads and very educational.
I solved my problem. I was using upsample="bilinear" rather than
upsampling="bilinear" and fixing this gave the expected results. But if
not for my stupid typo, I would not have had a chance to read those
threads and google others regarding upsampling.
Thanks for the assist,
-Steve
On 8/20/2020 10:13 AM, Rahkonen Jukka (MML) wrote:
Hi,
Resampling is science that would be nice to understand. Unfortunately I don't
but I think that this thread is worth reading
osgeo-org.1560.x6.nabble.com/gdal-dev-downsampling-geotiff-with-a-low-pass-filter-td5385890.html.
In this gis.SE question cubic spline was considered good
https://gis.stackexchange.com/questions/30627/smoothing-reinterpolating-raster-with-gdal.
-Jukka-
-----Alkuperäinen viesti-----
Lähettäjä: Stephen Woodbridge <stephenwoodbridg...@gmail.com>
Lähetetty: torstai 20. elokuuta 2020 16.58
Vastaanottaja: Rahkonen Jukka (MML) <jukka.rahko...@maanmittauslaitos.fi>
Aihe: Re: [gdal-dev] I have a problem getting higher resolution in a VRT file
Hi Jukka,
Any thoughts on what would be a better way to upsample and image using GDAL?
I assumed, maybe incorrectly, that if I’m up sampling between two pixels with
values of say 1 and 2 that a new pixel 50% between them would get a value of
1.5 and at 25% would get a value 1.25 etc. using linear interpolation and
bilinear would also account for rows above and below the current row.
Even, I specified resampling=“bilinear” in the vrt file is this ignored?
Thanks, Steve
Sent from my iPhone
On Aug 20, 2020, at 8:23 AM, jratike80 <jukka.rahko...@maanmittauslaitos.fi>
wrote:
Even Rouault-2 wrote
...
By default, VRT uses nearest resampling. You must specify something else.
Look for "A resampling attribute can be specified" in
https://gdal.org/drivers/raster/vrt.html
...
--
Actually in the provided .vrt file I can see <SimpleSource
resample="bilinear">
But isn't bilinear unsuitable for upsampling and some more blurring
method might work better?
-Jukka Rahkonen-
--
Sent from: http://osgeo-org.1560.x6.nabble.com/GDAL-Dev-f3742093.html
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