Dear list,
I have two rasters with elevation data (DEM and buildings, both floating point) which I would like to overlay so that the resulting raster obtains the summarized z-values of both rasters.
So I tried the r.patch and the r.mapcalculator with the result of just overlaid layers. E.g. at one cell where the DEM holds the z-value 435.0 m and the building raster the z-value 10.1 there still remain the 435.1 m in the resulting raster.
In case of r.mapcalculator, I used the Layer A + Layer B option.
How can I get the summarized values of both raster layers?
Regards
Christian
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hi,
r.mapcalc sum=map1+map2 would not help?
j
2008/5/20, christian Brandt <chrisbrandt74@hotmail.com>:
Dear list,
I have two rasters with elevation data (DEM and buildings, both floating
point) which I would like to overlay so that the resulting raster obtains
the summarized z-values of both rasters.
So I tried the r.patch and the r.mapcalculator with the result of just
<physically> overlaid layers. E.g. at one cell where the DEM holds the
z-value 435.0 m and the building raster the z-value 10.1 there still remain
the 435.1 m in the resulting raster.
In case of r.mapcalculator, I used the Layer A + Layer B option.
How can I get the summarized values of both raster layers?
Regards
Christian
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It appears that you don't want to add the rasters but be able to query
both values at once. From the command line you can use
r.what.rast rast=raster_1,raster_2 <missing coordinates part, don't
have grass in front of me now>
and you will get the values for both rasters at the desired coords. I
don't know how to do that using the grass GUI though
Cheers
Daniel
On Tue, May 20, 2008 at 6:49 AM, <jachym.cepicky@gmail.com> wrote:
hi,
r.mapcalc sum=map1+map2 would not help?
j
2008/5/20, christian Brandt <chrisbrandt74@hotmail.com>:
Dear list,
I have two rasters with elevation data (DEM and buildings, both floating
point) which I would like to overlay so that the resulting raster obtains
the summarized z-values of both rasters.
So I tried the r.patch and the r.mapcalculator with the result of just
<physically> overlaid layers. E.g. at one cell where the DEM holds the
z-value 435.0 m and the building raster the z-value 10.1 there still remain
the 435.1 m in the resulting raster.
In case of r.mapcalculator, I used the Layer A + Layer B option.
How can I get the summarized values of both raster layers?
Regards
Christian
_________________________________________________________________
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Spaces. It's easy!
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URL: http://les-ejk.cz
GPG: http://www.les-ejk.cz/pgp/jachym_cepicky-gpg.pub
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Hi Daniel, hi Jachym, hi list!
I am very sorry but I couldn’t get back earlier to your replies.
What I want to do is to get just one with combined elevation data from DGM raster and buildings raster
Hence I tried the r.mapcalculator as follows:
r.mapcalculator amap=dgm bmap=geb formula=A+B outfile=dgm_geb
The result just shows the same cell configuration as in the building raster but with elevation data just from the DGM.
Regards
Christian
Date: Tue, 20 May 2008 09:17:30 -0300
From: daniel.victoria@gmail.com
To: jachym.cepicky@gmail.com
Subject: Re: [GRASS-user] raster analysis: hot to get summarized values of two rasters
CC: chrisbrandt74@hotmail.com; grass-user@lists.osgeo.org
It appears that you don’t want to add the rasters but be able to query
both values at once. From the command line you can use
r.what.rast rast=raster_1,raster_2 <missing coordinates part, don’t
have grass in front of me now>
and you will get the values for both rasters at the desired coords. I
don’t know how to do that using the grass GUI though
Cheers
Daniel
On Tue, May 20, 2008 at 6:49 AM, jachym.cepicky@gmail.com wrote:
hi,
r.mapcalc sum=map1+map2 would not help?
j
2008/5/20, christian Brandt chrisbrandt74@hotmail.com:
Dear list,
I have two rasters with elevation data (DEM and buildings, both floating
point) which I would like to overlay so that the resulting raster obtains
the summarized z-values of both rasters.
So I tried the r.patch and the r.mapcalculator with the result of just
overlaid layers. E.g. at one cell where the DEM holds the
z-value 435.0 m and the building raster the z-value 10.1 there still remain
the 435.1 m in the resulting raster.
In case of r.mapcalculator, I used the Layer A + Layer B option.
How can I get the summarized values of both raster layers?
Regards
Christian
Invite your mail contacts to join your friends list with Windows Live
Spaces. It’s easy!
http://spaces.live.com/spacesapi.aspx?wx_action=create&wx_url=/friends.aspx&mkt=en-us
–
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e-mail: jachym.cepicky gmail com
URL: http://les-ejk.cz
GPG: http://www.les-ejk.cz/pgp/jachym_cepicky-gpg.pub
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On Tue, 2008-05-27 at 12:05 +0000, christian Brandt wrote:
What I want to do is to get just one <elevation-raster> with combined
elevation data from DGM raster and buildings raster
Hence I tried the r.mapcalculator as follows:
r.mapcalculator amap=dgm bmap=geb formula=A+B outfile=dgm_geb
Dear Christian,
r.mapcalc or r.mapcalculator should work.
Just some ideas (which you might have tested already, but anyway... ):
1. check the range of your "dgm" and "geb" data to be sure that both
have "valid" values
r.info -r dgm
r.info -r geb
(or use r.describe to list all values contained in your maps)
2. check the computational extent in you LOCATION:
g.region -p
or why not set directly to match the extent of one of your maps:
g.region rast=dgm
Nikos
If you are getting the output map with the same configuration as the
buildings, could it be that the places where there are no buildings
you have NULL values? So, when you add the maps NULL + anything = NULL
Try changing the nulls to zero in the buildings map (r.null is your
friend) and the add the maps.
Daniel
On Tue, May 27, 2008 at 9:14 AM, Nikos Alexandris
<nikos.alexandris@felis.uni-freiburg.de> wrote:
On Tue, 2008-05-27 at 12:05 +0000, christian Brandt wrote:
What I want to do is to get just one <elevation-raster> with combined
elevation data from DGM raster and buildings raster
Hence I tried the r.mapcalculator as follows:
r.mapcalculator amap=dgm bmap=geb formula=A+B outfile=dgm_geb
Dear Christian,
r.mapcalc or r.mapcalculator should work.
Just some ideas (which you might have tested already, but anyway... ):
1. check the range of your "dgm" and "geb" data to be sure that both
have "valid" values
r.info -r dgm
r.info -r geb
(or use r.describe to list all values contained in your maps)
2. check the computational extent in you LOCATION:
g.region -p
or why not set directly to match the extent of one of your maps:
g.region rast=dgm
Nikos