[Qgis-developer] Processing with raster files > 4GB
G. Allegri
giohappy at gmail.com
Wed Nov 19 02:25:57 PST 2014
And do you have problems with GRASS (directly, not through Processing)?
In GRASS7 you can even drectly write to Geotiff without passing through the
internal format (http://grass.osgeo.org/grass70/manuals/r.external.out.html
).
If GDAL is built with bigtiff support there souldn't be problems...
giovanni
2014-11-19 10:44 GMT+01:00 Andreas Neumann <a.neumann at carto.net>:
> Hi Giovanni,
>
> I need to change all pixels that have the value of 249 to a value of 255.
> All other pixels should stay at their value.
>
> Andreas
>
> Am 2014-11-19 10:21, schrieb G. Allegri:
>
>> From my grayscale tiff images I want to replace one pixel value
>>>
>> (249) with white (255). All other pixels should stay at the value they
>> have.
>> >
>> > I came across https://github.com/chiatt/gdal_reclassify [1] - but
>> this reclassifies all pixels, not only selected ones.
>> >
>> > Maybe I could use http://www.gdal.org/gdal_calc.html [2] with a
>> conditional syntax?
>>
>> Hi Andreas, do you need to change the value of one specific pixel
>> only? I mean the pixel at [x,y] index?
>>
>> giovanni
>>
>>
>>> > Thanks,
>> > Andreas
>> >
>> > Am 2014-11-19 09:10, schrieb Carlos López PSIG:
>> >>
>> >> Hi Andreas,
>> >>
>> >> I also had problems to reclassify BIGTIFF with SAGA and GRASS!
>> >> Finally I used GDAL!
>> >>
>> >> Best regards,
>> >>
>> >> [2]
>> >>
>> >> CARLOS LÓPEZ QUINTANILLA
>> >>
>> >> www.psig.es [3] [2]
>>
>> >>
>> >> carlos.lopez at psig.es
>> >> +34 699.680.261
>> >>
>> >> 2014-11-19 9:05 GMT+01:00 Andreas Neumann <a.neumann at carto.net>:
>> >>
>> >>> Hi,
>> >>>
>> >>> I tried various tools, e.g.
>> >>>
>> >>> * SAGA reclassify
>> >>> * GRASS r.mapcalc
>> >>>
>> >>> Both work fine on smaller data sets, but fail on big data sets.
>> >>>
>> >>> This is on Win7 64bit, with the OSGeo4W installer. I have 8gb RAM
>> >>> and 40GB disk free on C:, more free space on other disks where
>> the
>> >>> data resides.
>> >>>
>> >>> I am not totally sure if it is the Bigtiff issue or some other
>> >>> issue. It is just a guess that maybe I am hitting a limit with
>> tiff.
>> >>> It is not fully transparent to me what Processing is doing in the
>> >>> background (what file formats with what options it creates).
>> >>>
>> >>> It may also be an issue with SAGA or GRASS directly.
>> >>>
>> >>> Thanks if you know anything,
>> >>> Andreas
>> >>>
>> >>> Am 2014-11-18 21:15, schrieb Giovanni Manghi:
>> >>>
>> >>> Hi,
>> >>>
>> >>> I am having a lot of troubles with large raster files and
>> >>> processing.
>> >>>
>> >>> The intermediate results can go >4GB. Processing stops with not
>> so
>> >>> helpful error messages.
>> >>>
>> >>> I wonder if processing is hitting the 4GB limit. Can I force
>> >>> processing
>> >>> to use the BIGTIFF option or a raster format that can handle >4GB
>> >>> files?
>> >>>
>> >>> Hi Andreas, what tool specifically?
>> >>>
>> >>> cheers
>> >>>
>> >>> -- Giovanni --
>> >>> _______________________________________________
>> >>> Qgis-developer mailing list
>> >>> Qgis-developer at lists.osgeo.org
>> >>> http://lists.osgeo.org/mailman/listinfo/qgis-developer [4] [1]
>> >>
>> >> _______________________________________________
>> >> Qgis-developer mailing list
>> >> Qgis-developer at lists.osgeo.org
>> >> http://lists.osgeo.org/mailman/listinfo/qgis-developer [4] [1]
>> >>
>> >>
>> >>
>> >> Links:
>> >> ------
>> >> [1] http://lists.osgeo.org/mailman/listinfo/qgis-developer [4]
>> >> [2] http://www.psig.es [3]
>> >
>> > _______________________________________________
>> > Qgis-developer mailing list
>> > Qgis-developer at lists.osgeo.org
>> > http://lists.osgeo.org/mailman/listinfo/qgis-developer [4]
>>
>> Links:
>> ------
>> [1] https://github.com/chiatt/gdal_reclassify
>> [2] http://www.gdal.org/gdal_calc.html
>> [3] http://www.psig.es
>> [4] http://lists.osgeo.org/mailman/listinfo/qgis-developer
>>
>
--
Giovanni Allegri
http://about.me/giovanniallegri
Twitter: https://twitter.com/_giohappy_
blog: http://blog.spaziogis.it
GEO+ geomatica in Italia http://bit.ly/GEOplus
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/qgis-developer/attachments/20141119/7828453f/attachment-0001.html>
More information about the Qgis-developer
mailing list