Thanks for quick response and sorry for delayed response from my side.
This is the second time , I have noticed that v.to.rast changes the region settings equal to display resolution in GRASS70.
As, it cannot be reproduced at test side.
I will send more data the next time.
At present, I have created another mapset for working on v.to.rast and my base rasters and vectors are kept securely in “PERMANENT” mapset. I haven’t faced the problem since.
Thanks again.
On Tue, Apr 10, 2012 at 9:30 PM, <grass-user-request@lists.osgeo.org> wrote:
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than “Re: Contents of grass-user digest…”Today’s Topics:
- Re: r.stream.extract Syntax Problem (Markus Metz)
- Re: v.to.rast in grass70 (Markus Metz)
Message: 1
Date: Tue, 10 Apr 2012 09:14:55 +0200
From: Markus Metz <markus.metz.giswork@googlemail.com>
Subject: Re: [GRASS-user] r.stream.extract Syntax Problem
To: Rich Shepard <rshepard@appl-ecosys.com>
Cc: grass-users@lists.osgeo.org
Message-ID:
<CAG+h=FFXNBRd8E_K88NeQPDGZXLDa71sxyDLJzez+a=tyGjR8g@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1[Answering to your latest post in a new thread, but I prefer to keep
it all in one thread.]On Tue, Apr 10, 2012 at 1:54 AM, Rich Shepard <rshepard@appl-ecosys.com> wrote:
On Mon, 9 Apr 2012, Markus Metz wrote:
The computational region should be aligned to the DEM in order to get
accurate results. Aligning to the resolution of the DEM is not enough,
i.e. you should use g.region align=DEM instead of g.region res=XXX -a.
r.stream.extract should work if only a subregion is to be analysed by
setting the computational region accordingly and/or creating a MASK e.g.
for a specific basin.Markus, madi, et al.:
The region does need to be set with a mask (in my case, and based on the
v.to.rast output of the individual subbasins).v.to.rast? Basins as created by r.watershed, r.stream.basins and
r.water.outlet are already raster maps.The last advice in the example on the manual page is to compare the
weighted and unweighted extracted stream maps and “see which looks better.”
As a newcomer to this module I have no experience on what “better” looks
like.Attached are two .pdf files. One shows the weighted output streams, the
other the unweighted output streams. Both have the vector streams overlaid
on them. The weighted output has a solid yellow background and I don’t know
what that represents.In this case there is indeed no answer to “what looks better” because
both look terrible, to be honest. Something terrible must have
happened to the DEM, or there are indeed completely flat areas in the
west. If the aim is to extract streams that resemble the digitized
vector lines, the DEM you used seems to be not suitable. You could try
to run r.stream.extract with the DEM as the only input and a larger
threshold. The region should be aligned to the DEM first with g.region
-p align=dem. If that produces reasonable results, you can try to
fine-tune by adjusting the threshold and supplying a (weighed)
accumulation map as additional input.Markus M
PS: Please do not change the thread all the time. With regard to this
subject, you have started now the 7th or so thread, I lost count,
impossible for anyone to follow.
Message: 2
Date: Tue, 10 Apr 2012 10:01:11 +0200
From: Markus Metz <markus.metz.giswork@googlemail.com>
Subject: Re: [GRASS-user] v.to.rast in grass70
To: Paulo van Breugel <p.vanbreugel@gmail.com>
Cc: grass-user@lists.osgeo.org
Message-ID:
<CAG+h=FFKW0U9XPbw+4L93K1gci2tMbU8o-B4umSXudUAUc18Uw@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1On Mon, Apr 9, 2012 at 12:08 PM, Paulo van Breugel
<p.vanbreugel@gmail.com> wrote:I can confirm there are issues in how GRASS 7 handles region settings. In my
case, when using v.to.rast, the region settings are reset to the default,
i.e., the raster is converted using the default region settings rather then
the current. I am now at revision 51177. In a previous revision (51117) I
had a problem with region settings when using r.patch, see Ticket #1636
(http://trac.osgeo.org/grass/ticket/1636). These issues seem to be
independend of the mapset (it happens in both PERMANENT and other mapsets).I can not reproduce this problem. I tested in the North Carolina
dataset, mapset user1.I displayed boundary_county, zoomed to the default region. Then I
zoomed to a small part of the boundary_county vector and set the
region from display. Then I zoomed to a different part of the vector
that does not overlap with the current region. Thus the current
region, the default region, and the display extents were all different
from each other. Then I ran v.to.rast on the boundary_county vector.
v.to.rast correctly used the current region and nothing was changed
after v.to.rast was completed. This is r51306.Markus M
Paulo
On 04/09/2012 08:44 AM, Pankaj Kr Sharma wrote:
Dear Grass users and developers,
I just noticed that in grass70 , the v.to.rast module changes computational
region / current region
resolution to the display extent and resolution after finishing.My maps are in “PERMANENT” mapset. And, I have tried a number of options ,
but cannot reset the resolution of raster thus created to the required
resolution.Thanks.
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