[gdal-dev] gdalwarp makes landcover files blocky when shrinking
mathuin at gmail.com
Fri Jan 27 13:00:55 EST 2012
I've never seen gdaladdo -- neat command! Alas, the overviews are the
wrong way 'round -- I don't need to zoom out, I need to zoom in.
gdaladdo doesn't handle fractional scale values well, so I can't make
something bigger out of something smaller like I can with gdalwarp.
mathuin at gmail dot com
On Thu, Jan 26, 2012 at 20:01, Chaitanya kumar CH
<chaitanya.ch at gmail.com> wrote:
> Try gdaladdo  with the resampling algo set to 'mode'. If you use the -ro
> option, it will create an external overview. Check your output with
> different combinations of levels.
> : http://www.gdal.org/gdaladdo.html
> On Fri, Jan 27, 2012 at 5:09 AM, John Twilley <mathuin at gmail.com> wrote:
>> I am working with elevation and landcover data downloaded from the
>> USGS. I use gdalwarp to convert the data to a much smaller pixel. The
>> elevation data works very nicely with cubic resampling, but the only
>> resampling that works at all for the landcover data is
>> nearest-neighbor and that's very blocky. When I last worked with
>> landcover data, I used a majority algorithm which produced smoother
>> output -- but that algorithm is not implemented in gdalwarp.
>> I am looking over the source to gdalwarp to see how hard it is to add
>> a new algorithm. Other than that, though, what options are available
>> to me? Thanks in advance!
>> mathuin at gmail dot com
>> gdal-dev mailing list
>> gdal-dev at lists.osgeo.org
> Best regards,
> Chaitanya kumar CH.
> 17.2416N 80.1426E
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