Surely a stupid question, but I can’t find a way to clip a raster on the base of the region settings and/or the base of a vector. I can MASK, I can reclass, but I can’t clip!
Furthermore, is it possible to rotate a raster without the use of a 1st polynomial rectification through GCPs?
Giovanni
Hi,
if you already have a raster that fits your region then simply create a
MASK and just create a new raster with r.mapcalc.
r.mapcalc clipped_rast=rast
(r.mapcalc works only on the MASK so you can quickly clip any raster
like that).
On Fri, 2008-01-25 at 00:15 +0100, G. Allegri wrote:
Surely a stupid question, but I can't find a way to clip a raster on
the base of the region settings and/or the base of a vector. I can
MASK, I can reclass, but I can't clip!
Furthermore, is it possible to rotate a raster without the use of a
1st polynomial rectification through GCPs?Giovanni
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Nikos Alexandris
.
Department of Remote Sensing & Landscape Information Systems
Faculty of Forestry & Environmental Sciences, Albert-Ludwigs-University Freiburg
.
Tel. +49 (0) 761 203 3697 / Fax. +49 (0) 761 203 3701 / Skype: Nikos.Alexandris
.
Address: Tennenbacher str. 4, D-79106 Freiburg i. Br., Germany
I don’t have a raster that fits my region. I should create a vector with v.in.region, rasterize it and use it as a MASK… well, I hoped there was something more linear. The same could be used to clip on the base of a polygon.
The unsolved problem is rotation (and shift): making affine tranformations using just a x-shift and y-shift parameter, and a rotation angle having set a point as origin (or just around the “center” of the raster).
2008/1/25, Nikos Alexandris <nikos.alexandris@felis.uni-freiburg.de>:
Hi,
if you already have a raster that fits your region then simply create a
MASK and just create a new raster with r.mapcalc.r.mapcalc clipped_rast=rast
(r.mapcalc works only on the MASK so you can quickly clip any raster
like that).On Fri, 2008-01-25 at 00:15 +0100, G. Allegri wrote:
Surely a stupid question, but I can’t find a way to clip a raster on
the base of the region settings and/or the base of a vector. I can
MASK, I can reclass, but I can’t clip!
Furthermore, is it possible to rotate a raster without the use of a
1st polynomial rectification through GCPs?Giovanni
grass-user mailing list
grass-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-user
–
Nikos Alexandris
.
Department of Remote Sensing & Landscape Information Systems
Faculty of Forestry & Environmental Sciences, Albert-Ludwigs-University Freiburg
.
Tel. +49 (0) 761 203 3697 / Fax. +49 (0) 761 203 3701 / Skype: Nikos.Alexandris
.
Address: Tennenbacher str. 4, D-79106 Freiburg i. Br., Germany
Although I don't know how (!) I read in a post about i.rectify... Why
don't you dig-up the man page...
Cheers,
Nikos.
On Fri, 2008-01-25 at 00:53 +0100, G. Allegri wrote:
I don't have a raster that fits my region. I should create a vector
with v.in.region, rasterize it and use it as a MASK... well, I hoped
there was something more linear. The same could be used to clip on the
base of a polygon.The unsolved problem is rotation (and shift): making affine
tranformations using just a x-shift and y-shift parameter, and a
rotation angle having set a point as origin (or just around the
"center" of the raster).2008/1/25, Nikos Alexandris <nikos.alexandris@felis.uni-freiburg.de>:
Hi,
if you already have a raster that fits your region then simply
create a
MASK and just create a new raster with r.mapcalc.
r.mapcalc clipped_rast=rast
(r.mapcalc works only on the MASK so you can quickly clip any
raster
like that).
On Fri, 2008-01-25 at 00:15 +0100, G. Allegri wrote:
> Surely a stupid question, but I can't find a way to clip a
raster on
> the base of the region settings and/or the base of a vector.
I can
> MASK, I can reclass, but I can't clip!
> Furthermore, is it possible to rotate a raster without the
use of a
> 1st polynomial rectification through GCPs?
>
> Giovanni
> _______________________________________________
> grass-user mailing list
> grass-user@lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/grass-user
--
Nikos Alexandris
.
Department of Remote Sensing & Landscape Information Systems
Faculty of Forestry & Environmental Sciences,
Albert-Ludwigs-University Freiburg
.
Tel. +49 (0) 761 203 3697 / Fax. +49 (0) 761 203 3701 /
Skype: Nikos.Alexandris
.
Address: Tennenbacher str. 4, D-79106 Freiburg i. Br., Germany
--
Nikos Alexandris
.
Department of Remote Sensing & Landscape Information Systems
Faculty of Forestry & Environmental Sciences, Albert-Ludwigs-University Freiburg
.
Tel. +49 (0) 761 203 3697 / Fax. +49 (0) 761 203 3701 / Skype: Nikos.Alexandris
.
Address: Tennenbacher str. 4, D-79106 Freiburg i. Br., Germany
Nikos, I ask because I’ve read almost all the pages of the manual. I use i.rectify: it is the tool to rectify rasters on the base of GCPs. This is not the case.
2008/1/25, Nikos Alexandris < nikos.alexandris@felis.uni-freiburg.de>:
Although I don’t know how (!) I read in a post about i.rectify… Why
don’t you dig-up the man page…Cheers,
Nikos.
On Fri, 2008-01-25 at 00:53 +0100, G. Allegri wrote:
I don’t have a raster that fits my region. I should create a vector
with v.in.region, rasterize it and use it as a MASK… well, I hoped
there was something more linear. The same could be used to clip on the
base of a polygon.The unsolved problem is rotation (and shift): making affine
tranformations using just a x-shift and y-shift parameter, and a
rotation angle having set a point as origin (or just around the
“center” of the raster).2008/1/25, Nikos Alexandris < nikos.alexandris@felis.uni-freiburg.de>:
Hi,if you already have a raster that fits your region then simply
create a
MASK and just create a new raster with r.mapcalc.r.mapcalc clipped_rast=rast
(r.mapcalc works only on the MASK so you can quickly clip any
raster
like that).On Fri, 2008-01-25 at 00:15 +0100, G. Allegri wrote:
Surely a stupid question, but I can’t find a way to clip a
raster on
the base of the region settings and/or the base of a vector.
I can
MASK, I can reclass, but I can’t clip!
Furthermore, is it possible to rotate a raster without the
use of a
1st polynomial rectification through GCPs?Giovanni
grass-user mailing list
grass-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-user
–
Nikos Alexandris
.
Department of Remote Sensing & Landscape Information Systems
Faculty of Forestry & Environmental Sciences,
Albert-Ludwigs-University Freiburg
.
Tel. +49 (0) 761 203 3697 / Fax. +49 (0) 761 203 3701 /
Skype: Nikos.Alexandris
.
Address: Tennenbacher str. 4, D-79106 Freiburg i. Br., Germany–
Nikos Alexandris
.
Department of Remote Sensing & Landscape Information Systems
Faculty of Forestry & Environmental Sciences, Albert-Ludwigs-University Freiburg
.
Tel. +49 (0) 761 203 3697 / Fax. +49 (0) 761 203 3701 / Skype: Nikos.Alexandris
.
Address: Tennenbacher str. 4, D-79106 Freiburg i. Br., Germany
G. Allegri wrote:
I don't have a raster that fits my region.
this will do it:
r.mapcalc 'regionrast = 1'
The unsolved problem is rotation (and shift): making affine
tranformations using just a x-shift and y-shift parameter, and a
rotation angle having set a point as origin (or just around the
"center" of the raster).
some ideas.
simple translation without rotation: r.region
90 deg rotation / flipping:
r.out.mat -> Matlab or GNU Octave.
ML>> array_rot = orig_array' ;
% flip array left-right or up-down
ML>> array_flip = fliplr( flipud( orig_array ) ) ;
r.in.mat
for rotation by angle you could do more complicated stuff in Matlab.
In GRASS i.rectify may be an option.
Hamish
____________________________________________________________________________________
Never miss a thing. Make Yahoo your home page.
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Hi Hamish, thanks for the hints. I’ve already tried using r.region, but it seemed to me it just managed boundaries. How could it be used to shift xy?
2008/1/25, Hamish < hamish_b@yahoo.com>:
G. Allegri wrote:
I don’t have a raster that fits my region.
this will do it:
r.mapcalc ‘regionrast = 1’The unsolved problem is rotation (and shift): making affine
tranformations using just a x-shift and y-shift parameter, and a
rotation angle having set a point as origin (or just around the
“center” of the raster).some ideas.
simple translation without rotation: r.region
90 deg rotation / flipping:
r.out.mat → Matlab or GNU Octave.
ML>> array_rot = orig_array’ ;
% flip array left-right or up-down
ML>> array_flip = fliplr( flipud( orig_array ) ) ;
r.in.matfor rotation by angle you could do more complicated stuff in Matlab.
In GRASS i.rectify may be an option.
Hamish
Never miss a thing. Make Yahoo your home page.
http://www.yahoo.com/r/hs
G. Allegri wrote:
Surely a stupid question, but I can't find a way to clip a raster on the
base of the region settings and/or the base of a vector. I can MASK, I can
reclass, but I can't clip!
r.resample will resample a map according to the current region
settings.
To clip to a vector map, convert the vector area(s) to a raster then
use it as a mask.
Furthermore, is it possible to rotate a raster without the use of a 1st
polynomial rectification through GCPs?
No.
You can translate and/or scale a map by changing its boundaries with
r.region, but the only tool to rotate or skew a map is i.rectify
(there isn't an r.rectify).
--
Glynn Clements <glynn@gclements.plus.com>