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Hi,<br>
<br>
I will have to do further testing about GRASS. On Windows (OSGeo4W
install) it does not work too well. It probably works better on
Linux.<br>
<br>
The gdal_calc.py solution works very fast though - glad that we came
to this solution!<br>
<br>
Andreas<br>
<br>
<div class="moz-cite-prefix">On 19.11.2014 11:25, G. Allegri wrote:<br>
</div>
<blockquote
cite="mid:CAB4g1=zQ7Sh8Qx3-0fAKoMKOC+QMhz55U4KAt_6ooJimdbexXg@mail.gmail.com"
type="cite">
<div dir="ltr">And do you have problems with GRASS (directly, not
through Processing)?
<div>In GRASS7 you can even drectly write to Geotiff without
passing through the internal format (<a moz-do-not-send="true"
href="http://grass.osgeo.org/grass70/manuals/r.external.out.html">http://grass.osgeo.org/grass70/manuals/r.external.out.html</a>).</div>
<div>If GDAL is built with bigtiff support there souldn't be
problems...</div>
<div><br>
</div>
<div>giovanni</div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">2014-11-19 10:44 GMT+01:00 Andreas
Neumann <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:a.neumann@carto.net" target="_blank">a.neumann@carto.net</a>></span>:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">Hi
Giovanni,<br>
<br>
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.<br>
<br>
Andreas<br>
<br>
Am 2014-11-19 10:21, schrieb G. Allegri:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex"><span
class="">
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
From my grayscale tiff images I want to replace one
pixel value<br>
</blockquote>
(249) with white (255). All other pixels should stay at
the value they<br>
have.<br>
><br>
</span>
> I came across <a moz-do-not-send="true"
href="https://github.com/chiatt/gdal_reclassify"
target="_blank">https://github.com/chiatt/gdal_reclassify</a>
[1] - but<span class=""><br>
this reclassifies all pixels, not only selected ones.<br>
><br>
</span>
> Maybe I could use <a moz-do-not-send="true"
href="http://www.gdal.org/gdal_calc.html"
target="_blank">http://www.gdal.org/gdal_calc.html</a>
[2] with a<span class=""><br>
conditional syntax?<br>
<br>
Hi Andreas, do you need to change the value of one
specific pixel<br>
only? I mean the pixel at [x,y] index?<br>
<br>
giovanni<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
</blockquote>
> Thanks,<br>
> Andreas<br>
><br>
> Am 2014-11-19 09:10, schrieb Carlos López PSIG:<br>
>><br>
>> Hi Andreas,<br>
>><br>
>> I also had problems to reclassify BIGTIFF with
SAGA and GRASS!<br>
>> Finally I used GDAL!<br>
>><br>
>> Best regards,<br>
>><br>
>> [2]<br>
>><br>
>> CARLOS LÓPEZ QUINTANILLA<br>
>><br>
</span>
>> <a moz-do-not-send="true"
href="http://www.psig.es" target="_blank">www.psig.es</a>
[3] [2]
<div>
<div class="h5"><br>
>><br>
>> <a moz-do-not-send="true"
href="mailto:carlos.lopez@psig.es" target="_blank">carlos.lopez@psig.es</a><br>
>> <a moz-do-not-send="true"
href="tel:%2B34%20699.680.261" value="+34699680261"
target="_blank">+34 699.680.261</a><br>
>><br>
>> 2014-11-19 9:05 GMT+01:00 Andreas Neumann
<<a moz-do-not-send="true"
href="mailto:a.neumann@carto.net" target="_blank">a.neumann@carto.net</a>>:<br>
>><br>
>>> Hi,<br>
>>><br>
>>> I tried various tools, e.g.<br>
>>><br>
>>> * SAGA reclassify<br>
>>> * GRASS r.mapcalc<br>
>>><br>
>>> Both work fine on smaller data sets, but
fail on big data sets.<br>
>>><br>
>>> This is on Win7 64bit, with the OSGeo4W
installer. I have 8gb RAM<br>
>>> and 40GB disk free on C:, more free
space on other disks where<br>
the<br>
>>> data resides.<br>
>>><br>
>>> I am not totally sure if it is the
Bigtiff issue or some other<br>
>>> issue. It is just a guess that maybe I
am hitting a limit with<br>
tiff.<br>
>>> It is not fully transparent to me what
Processing is doing in the<br>
>>> background (what file formats with what
options it creates).<br>
>>><br>
>>> It may also be an issue with SAGA or
GRASS directly.<br>
>>><br>
>>> Thanks if you know anything,<br>
>>> Andreas<br>
>>><br>
>>> Am 2014-11-18 21:15, schrieb Giovanni
Manghi:<br>
>>><br>
>>> Hi,<br>
>>><br>
>>> I am having a lot of troubles with large
raster files and<br>
>>> processing.<br>
>>><br>
>>> The intermediate results can go >4GB.
Processing stops with not<br>
so<br>
>>> helpful error messages.<br>
>>><br>
>>> I wonder if processing is hitting the
4GB limit. Can I force<br>
>>> processing<br>
>>> to use the BIGTIFF option or a raster
format that can handle >4GB<br>
>>> files?<br>
>>><br>
>>> Hi Andreas, what tool specifically?<br>
>>><br>
>>> cheers<br>
>>><br>
>>> -- Giovanni --<br>
>>> _______________________________________________<br>
>>> Qgis-developer mailing list<br>
>>> <a moz-do-not-send="true"
href="mailto:Qgis-developer@lists.osgeo.org"
target="_blank">Qgis-developer@lists.osgeo.org</a><br>
</div>
</div>
>>> <a moz-do-not-send="true"
href="http://lists.osgeo.org/mailman/listinfo/qgis-developer"
target="_blank">http://lists.osgeo.org/mailman/listinfo/qgis-developer</a>
[4] [1]<span class=""><br>
>><br>
>> _______________________________________________<br>
>> Qgis-developer mailing list<br>
>> <a moz-do-not-send="true"
href="mailto:Qgis-developer@lists.osgeo.org"
target="_blank">Qgis-developer@lists.osgeo.org</a><br>
</span>
>> <a moz-do-not-send="true"
href="http://lists.osgeo.org/mailman/listinfo/qgis-developer"
target="_blank">http://lists.osgeo.org/mailman/listinfo/qgis-developer</a>
[4] [1]<br>
>><br>
>><br>
>><br>
>> Links:<br>
>> ------<br>
>> [1] <a moz-do-not-send="true"
href="http://lists.osgeo.org/mailman/listinfo/qgis-developer"
target="_blank">http://lists.osgeo.org/mailman/listinfo/qgis-developer</a>
[4]<br>
>> [2] <a moz-do-not-send="true"
href="http://www.psig.es" target="_blank">http://www.psig.es</a>
[3]<span class=""><br>
><br>
> _______________________________________________<br>
> Qgis-developer mailing list<br>
> <a moz-do-not-send="true"
href="mailto:Qgis-developer@lists.osgeo.org"
target="_blank">Qgis-developer@lists.osgeo.org</a><br>
</span>
> <a moz-do-not-send="true"
href="http://lists.osgeo.org/mailman/listinfo/qgis-developer"
target="_blank">http://lists.osgeo.org/mailman/listinfo/qgis-developer</a>
[4]<br>
<br>
Links:<br>
------<br>
[1] <a moz-do-not-send="true"
href="https://github.com/chiatt/gdal_reclassify"
target="_blank">https://github.com/chiatt/gdal_reclassify</a><br>
[2] <a moz-do-not-send="true"
href="http://www.gdal.org/gdal_calc.html"
target="_blank">http://www.gdal.org/gdal_calc.html</a><br>
[3] <a moz-do-not-send="true" href="http://www.psig.es"
target="_blank">http://www.psig.es</a><br>
[4] <a moz-do-not-send="true"
href="http://lists.osgeo.org/mailman/listinfo/qgis-developer"
target="_blank">http://lists.osgeo.org/mailman/listinfo/qgis-developer</a><br>
</blockquote>
</blockquote>
</div>
<br>
<br clear="all">
<div><br>
</div>
-- <br>
<div class="gmail_signature">
<div dir="ltr">Giovanni Allegri<br>
<a moz-do-not-send="true"
href="http://about.me/giovanniallegri" target="_blank">http://about.me/giovanniallegri</a>
<div>Twitter: <a moz-do-not-send="true"
href="https://twitter.com/_giohappy_" target="_blank">https://twitter.com/_giohappy_</a></div>
<div>blog: <a moz-do-not-send="true"
href="http://blog.spaziogis.it" target="_blank">http://blog.spaziogis.it</a><br>
GEO+ geomatica in Italia <a moz-do-not-send="true"
href="http://bit.ly/GEOplus" target="_blank">http://bit.ly/GEOplus</a></div>
</div>
</div>
</div>
</blockquote>
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