Hello!
my name is Chiara, I'm currently using grass to postprocess netcdf data and peroform spatial analysis
I import netcdf bands separately, then reclassify the values (with external tables) and finally convert the area that i'm interested in into polygons.
while using r.reclass, the output raster has a lower resolution that the initial one. this parameter does not seem to be customizable. Of course I could change the resolution afterwords, but it would imply an interpolation, while the values of the initial raster are more reliable...
how could I solve this problem?
thanks a lot!
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Chiara Scaini wrote:
Hello!
my name is Chiara, I'm currently using grass to postprocess netcdf data
and peroform spatial analysis
Hello Chiara!
I import netcdf bands separately, then reclassify the values (with
external tables) and finally convert the area that i'm interested in
into polygons.
while using r.reclass, the output raster has a lower resolution that
the initial one.
In general, the resolution and extent of "new" raster maps derived from raster
processing modules, are the ones of the current region (aka computational
region) which are set by the user with the "g.region" module.
this parameter does not seem to be customizable.
Not from "within" the r.reclass module, and, in general not "within from"
almost all raster processing modules. It is g.region that controls that.
Of course I could change the resolution afterwords, but it would imply an
interpolation, while the values of the initial raster are more
reliable...
how could I solve this problem?
Right! This will not be necessary, of course, if the user has properly set
from the beginning...
g.region rast=Some_NETCDF_Band -p
Best of success with your work,
Nikos
Chiara Scaini wrote:
while using r.reclass, the output raster has a lower resolution that
the initial one. this parameter does not seem to be customizable.
A reclass map always has the same bounds and resolution as its base
map. It cannot be otherwise, as a reclass map is simply a table
listing the mapping between categories.
However, with few exceptions, GRASS modules which read raster maps
automatically resample them to the current region. See the g.region
manual page for details on displaying and changing the current region.
--
Glynn Clements <glynn@gclements.plus.com>
Hi all!
and thanks Alex, Nikos and Glynn for the reply
yes, setting the g.region, all the raster have the same resolution of the netcdf band!
problem solved 
thanks
Chiara
On Wed, 3 Jul 2013 03:10:18 +0100, Glynn Clements wrote:
Chiara Scaini wrote:
while using r.reclass, the output raster has a lower resolution that
the initial one. this parameter does not seem to be customizable.
A reclass map always has the same bounds and resolution as its base
map. It cannot be otherwise, as a reclass map is simply a table
listing the mapping between categories.
However, with few exceptions, GRASS modules which read raster maps
automatically resample them to the current region. See the g.region
manual page for details on displaying and changing the current region.
WARNING / LEGAL TEXT: This message is intended only for the use of the
individual or entity to which it is addressed and may contain
information which is privileged, confidential, proprietary, or exempt
from disclosure under applicable law. If you are not the intended
recipient or the person responsible for delivering the message to the
intended recipient, you are strictly prohibited from disclosing,
distributing, copying, or in any way using this message. If you have
received this communication in error, please notify the sender and
destroy and delete any copies you may have received.
http://www.bsc.es/disclaimer