[GRASS-user] Grass, Python, mapcalc

GRASS GRASS user
1

Thanks Sotiris,

I’ve tried your suggestion but converted it to Python because I’m on Windows.

This is my script:
grass.run_command(‘g.mremove’, rast = (‘out*’))
grass.mapcalc(‘sun=global1’, quiet=False, verbose=False, overwrite=True)
for x in range(2, 10, 1):
exp = ‘out=sun+global’ + str(x)
print exp
grass.mapcalc(exp, quiet=False, verbose=False, overwrite=True)

grass.run_command(‘g.rename’, flag=‘o’, rast = (‘out’,‘sun’))

This doesn’t result in the expected outcome.

sun is equal to global1 and no values are added

out is global1+global2 but is no more values are added. But mapcalc is called several times.
I’ve tested this with:
r.what --v -f -n input=global1 east_north=156287.225281,383024.737026
r.what --v -f -n input=sun east_north=156287.225281,383024.737026
r.what --v -f -n input=out east_north=156287.225281,383024.737026

Not only am I a new user to GRASS but I’m also still a novice in Python. Most likely it is something in my script.

If somebody has a different approach to get the solar radiation of a whole year I’m happy to try that.

Thanks,

Paul

···

Date: Fri, 28 Dec 2012 14:36:15 +0200
From: “S. Koukoulas (lists)” <sotkouklistes@gmail.com>
To: grass-user@lists.osgeo.org
Subject: Re: [GRASS-user] Grass, Python, mapcalc
Message-ID: <50DD923F.806@gmail.com>
Content-Type: text/plain; charset=windows-1252

To my experience with r.mapcalc you cannot do what yo do with
programming languages… e.g. i=i+1 will not work directly. Instead you
could try a more indirect way, something like (here is an example with
bash shell script):

#g.mremove rast=out* (to remove previous stuff, if needed)
r.mapcalc sun=global1
for a in ?seq 2 10?; do
r.mapcalc out = sun + global$a
g.rename --o rast=out,sun
done

basically the main idea is to use an intermediate map and then before
the loop ends, pass it (with g.rename) to the map variable you want.
There might be a more elegant way with python, but hopefully this shell
script example might help you.
HTH,
sotiris

2

Paul,
First, Daniel's example worked for me - (I wasn't aware of the changes
in r.mapcalc and in a similar problem I made use of older posts to solve
my problems).

Now, if you want to go the other way then you must make sure that
globalx changes to global2, global3 etc. So your problem should be in
this line:
exp = 'out=sun+global' + str(x)

I am not using python, but you should only join the strings of 'global'
and str(x). e.g. 'global'+str(x) should become one everytime. You could
do this before calling mapcalc e.g. g='global'+str(x)
exp = 'out=sun+g' OR just check the use of brackets and quotes in the
"exp=..." line
best
sotiris

On 12/28/2012 03:08 PM, Paul Meems wrote:

Thanks Sotiris,

I've tried your suggestion but converted it to Python because I'm on
Windows.
This is my script:
grass.run_command('g.mremove', rast = ('out*'))
grass.mapcalc('sun=global1', quiet=False, verbose=False, overwrite=True)
for x in range(2, 10, 1):
  exp = 'out=sun+global' + str(x)
  print exp
  grass.mapcalc(exp, quiet=False, verbose=False, overwrite=True)
  grass.run_command('g.rename', flag='o', rast = ('out','sun'))

This doesn't result in the expected outcome.
sun is equal to global1 and no values are added
out is global1+global2 but is no more values are added. But mapcalc is
called several times.
I've tested this with:
r.what --v -f -n input=global1 east_north=156287.225281,383024.737026
r.what --v -f -n input=sun east_north=156287.225281,383024.737026
r.what --v -f -n input=out east_north=156287.225281,383024.737026

Not only am I a new user to GRASS but I'm also still a novice in
Python. Most likely it is something in my script.

If somebody has a different approach to get the solar radiation of a
whole year I'm happy to try that.

Thanks,

Paul

    Date: Fri, 28 Dec 2012 14:36:15 +0200
    From: "S. Koukoulas (lists)" <sotkouklistes@gmail.com
    <mailto:sotkouklistes@gmail.com>>
    To: grass-user@lists.osgeo.org <mailto:grass-user@lists.osgeo.org>
    Subject: Re: [GRASS-user] Grass, Python, mapcalc
    Message-ID: <50DD923F.806@gmail.com <mailto:50DD923F.806@gmail.com>>
    Content-Type: text/plain; charset=windows-1252

    To my experience with r.mapcalc you cannot do what yo do with
    programming languages... e.g. i=i+1 will not work directly.
    Instead you
    could try a more indirect way, something like (here is an example with
    bash shell script):

    #g.mremove rast=out* (to remove previous stuff, if needed)
    r.mapcalc sun=global1
    for a in ?seq 2 10?; do
    r.mapcalc out = sun + global$a
    g.rename --o rast=out,sun
    done

    basically the main idea is to use an intermediate map and then before
    the loop ends, pass it (with g.rename) to the map variable you want.
    There might be a more elegant way with python, but hopefully this
    shell
    script example might help you.
    HTH,
    sotiris

_______________________________________________
grass-user mailing list
grass-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-user

3

Dear Paul,

having said all that for r.mapcalc, I wonder whether you really need
mapcalc. In your case,
couldn't you just use the * r.series * command with Sum (and perhaps
g.mlist can help you make a list of all the daily maps).

I think that it might be faster as well.
best,
sotiris

On 12/28/2012 03:08 PM, Paul Meems wrote:

Thanks Sotiris,

I've tried your suggestion but converted it to Python because I'm on
Windows.
This is my script:
grass.run_command('g.mremove', rast = ('out*'))
grass.mapcalc('sun=global1', quiet=False, verbose=False, overwrite=True)
for x in range(2, 10, 1):
  exp = 'out=sun+global' + str(x)
  print exp
  grass.mapcalc(exp, quiet=False, verbose=False, overwrite=True)
  grass.run_command('g.rename', flag='o', rast = ('out','sun'))

This doesn't result in the expected outcome.
sun is equal to global1 and no values are added
out is global1+global2 but is no more values are added. But mapcalc is
called several times.
I've tested this with:
r.what --v -f -n input=global1 east_north=156287.225281,383024.737026
r.what --v -f -n input=sun east_north=156287.225281,383024.737026
r.what --v -f -n input=out east_north=156287.225281,383024.737026

Not only am I a new user to GRASS but I'm also still a novice in
Python. Most likely it is something in my script.

If somebody has a different approach to get the solar radiation of a
whole year I'm happy to try that.

Thanks,

Paul

    Date: Fri, 28 Dec 2012 14:36:15 +0200
    From: "S. Koukoulas (lists)" <sotkouklistes@gmail.com
    <mailto:sotkouklistes@gmail.com>>
    To: grass-user@lists.osgeo.org <mailto:grass-user@lists.osgeo.org>
    Subject: Re: [GRASS-user] Grass, Python, mapcalc
    Message-ID: <50DD923F.806@gmail.com <mailto:50DD923F.806@gmail.com>>
    Content-Type: text/plain; charset=windows-1252

    To my experience with r.mapcalc you cannot do what yo do with
    programming languages... e.g. i=i+1 will not work directly.
    Instead you
    could try a more indirect way, something like (here is an example with
    bash shell script):

    #g.mremove rast=out* (to remove previous stuff, if needed)
    r.mapcalc sun=global1
    for a in ?seq 2 10?; do
    r.mapcalc out = sun + global$a
    g.rename --o rast=out,sun
    done

    basically the main idea is to use an intermediate map and then before
    the loop ends, pass it (with g.rename) to the map variable you want.
    There might be a more elegant way with python, but hopefully this
    shell
    script example might help you.
    HTH,
    sotiris

_______________________________________________
grass-user mailing list
grass-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-user

4

Hi Sotiris,

Thanks for your help.

I will have a look at the r.series.

Meanwhile I’ve discovered the graphical modeler. It is not working 100% in all cases but it does generates a Python script with all the necessary parameters.

This is my script so far, which seems to be working:
for x in range(1, 10, 1):
print “Working on day %d” % (x)

Create radiation for each day:

glob_rad = ‘global’ + str(x)
grass.run_command(‘r.sun’, flags = ‘s’, overwrite = True, elevin = ‘w001001@temp’, aspin = ‘aspect@temp’, slopein = ‘slope@temp’, glob_rad = glob_rad, day = x)

Combine the radiation file with the previous one:

if x == 2:
grass.run_command(“r.mapcalculator”, overwrite = True, amap = “global1”, bmap = “global2”, formula = “A+B”,
outfile = “suntemp2”)
elif x > 2:

Use temp name or else it won’t work:

amap = “suntemp” + str(x-1)
bmap = “global” + str(x) + “@temp”
outfile = “suntemp” + str(x)
grass.run_command(“r.mapcalculator”, overwrite = True, amap = amap, bmap = bmap, formula = “A+B”,
outfile = outfile)

Finalize:

grass.mapcalc(‘sun=’ + outfile, quiet=False, verbose=True, overwrite=True)

Clean up:

grass.run_command(‘g.mremove’, flags = ‘f’, rast = “suntemp*”)
grass.run_command(‘g.mremove’, flags = ‘f’, rast = “global*”)
print “Done”

Thanks

···

Paul

2012/12/28 S. Koukoulas (lists) <sotkouklistes@gmail.com>

Dear Paul,

having said all that for r.mapcalc, I wonder whether you really need
mapcalc. In your case,
couldn’t you just use the * r.series * command with Sum (and perhaps
g.mlist can help you make a list of all the daily maps).

I think that it might be faster as well.
best,
sotiris

On 12/28/2012 03:08 PM, Paul Meems wrote:

Thanks Sotiris,

I’ve tried your suggestion but converted it to Python because I’m on
Windows.
This is my script:
grass.run_command(‘g.mremove’, rast = (‘out*’))
grass.mapcalc(‘sun=global1’, quiet=False, verbose=False, overwrite=True)
for x in range(2, 10, 1):
exp = ‘out=sun+global’ + str(x)
print exp
grass.mapcalc(exp, quiet=False, verbose=False, overwrite=True)
grass.run_command(‘g.rename’, flag=‘o’, rast = (‘out’,‘sun’))

This doesn’t result in the expected outcome.
sun is equal to global1 and no values are added
out is global1+global2 but is no more values are added. But mapcalc is
called several times.
I’ve tested this with:
r.what --v -f -n input=global1 east_north=156287.225281,383024.737026
r.what --v -f -n input=sun east_north=156287.225281,383024.737026
r.what --v -f -n input=out east_north=156287.225281,383024.737026

Not only am I a new user to GRASS but I’m also still a novice in
Python. Most likely it is something in my script.

If somebody has a different approach to get the solar radiation of a
whole year I’m happy to try that.

Thanks,

Paul

Date: Fri, 28 Dec 2012 14:36:15 +0200
From: “S. Koukoulas (lists)” <sotkouklistes@gmail.com

mailto:[sotkouklistes@gmail.com](mailto:sotkouklistes@gmail.com)>
To: grass-user@lists.osgeo.org mailto:[grass-user@lists.osgeo.org](mailto:grass-user@lists.osgeo.org)

Subject: Re: [GRASS-user] Grass, Python, mapcalc

Message-ID: <50DD923F.806@gmail.com mailto:[50DD923F.806@gmail.com](mailto:50DD923F.806@gmail.com)>

Content-Type: text/plain; charset=windows-1252

To my experience with r.mapcalc you cannot do what yo do with
programming languages… e.g. i=i+1 will not work directly.
Instead you
could try a more indirect way, something like (here is an example with
bash shell script):

#g.mremove rast=out* (to remove previous stuff, if needed)
r.mapcalc sun=global1
for a in ?seq 2 10?; do
r.mapcalc out = sun + global$a
g.rename --o rast=out,sun
done

basically the main idea is to use an intermediate map and then before
the loop ends, pass it (with g.rename) to the map variable you want.
There might be a more elegant way with python, but hopefully this
shell
script example might help you.
HTH,
sotiris

grass-user mailing list
grass-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-user

5

Hi Paul,

I think one of your problems is… using windows :wink: I have heard that the Windows version of GRASS works a LOT better than it used to, but GRASS was actually the reason I switched to Linux a couple of years ago. Back then it just ran better in Linux - a lot better. Since then, I’ve never gone back to Windows because I’m very satisfied with Linux, not just with GRASS but with everything else I do with the computer. Of course, Linux vs. Windows is a whole different story and doesn’t belong in this list, but that was my experience.

If you’re wanting to use GRASS in a headless Ubuntu server anyway, why don’t you set up a Linux machine or at least a Linux installation in a virtual machine and play around with it there? There everything should work well and the development environment would match your production environment. OSGeo has a great live installation including all of the latest Geo software, Python, etc. - everything the;heart could desire. since I’m out and about at the moment I can’t send you the address, but just Google for an OSGeo live installation and you’ll see it right away.

Hope that helps,
Daniel

···

Paul

2012/12/28 S. Koukoulas (lists) <sotkouklistes@gmail.com>

Dear Paul,

having said all that for r.mapcalc, I wonder whether you really need
mapcalc. In your case,
couldn’t you just use the * r.series * command with Sum (and perhaps
g.mlist can help you make a list of all the daily maps).

I think that it might be faster as well.
best,
sotiris

On 12/28/2012 03:08 PM, Paul Meems wrote:

Thanks Sotiris,

I’ve tried your suggestion but converted it to Python because I’m on
Windows.
This is my script:
grass.run_command(‘g.mremove’, rast = (‘out*’))
grass.mapcalc(‘sun=global1’, quiet=False, verbose=False, overwrite=True)
for x in range(2, 10, 1):
exp = ‘out=sun+global’ + str(x)
print exp
grass.mapcalc(exp, quiet=False, verbose=False, overwrite=True)
grass.run_command(‘g.rename’, flag=‘o’, rast = (‘out’,‘sun’))

This doesn’t result in the expected outcome.
sun is equal to global1 and no values are added
out is global1+global2 but is no more values are added. But mapcalc is
called several times.
I’ve tested this with:
r.what --v -f -n input=global1 east_north=156287.225281,383024.737026
r.what --v -f -n input=sun east_north=156287.225281,383024.737026
r.what --v -f -n input=out east_north=156287.225281,383024.737026

Not only am I a new user to GRASS but I’m also still a novice in
Python. Most likely it is something in my script.

If somebody has a different approach to get the solar radiation of a
whole year I’m happy to try that.

Thanks,

Paul

Date: Fri, 28 Dec 2012 14:36:15 +0200
From: “S. Koukoulas (lists)” <sotkouklistes@gmail.com

mailto:[sotkouklistes@gmail.com](mailto:sotkouklistes@gmail.com)>
To: grass-user@lists.osgeo.org mailto:[grass-user@lists.osgeo.org](mailto:grass-user@lists.osgeo.org)

Subject: Re: [GRASS-user] Grass, Python, mapcalc

Message-ID: <50DD923F.806@gmail.com mailto:[50DD923F.806@gmail.com](mailto:50DD923F.806@gmail.com)>

Content-Type: text/plain; charset=windows-1252

To my experience with r.mapcalc you cannot do what yo do with
programming languages… e.g. i=i+1 will not work directly.
Instead you
could try a more indirect way, something like (here is an example with
bash shell script):

#g.mremove rast=out* (to remove previous stuff, if needed)
r.mapcalc sun=global1
for a in ?seq 2 10?; do
r.mapcalc out = sun + global$a
g.rename --o rast=out,sun
done

basically the main idea is to use an intermediate map and then before
the loop ends, pass it (with g.rename) to the map variable you want.
There might be a more elegant way with python, but hopefully this
shell
script example might help you.
HTH,
sotiris

grass-user mailing list
grass-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-user

6

Daniel,

I could not agree more WRT Linux/Ubuntu; I come from a Mac background and I think for GRASS, Macintosh is superior to MS-Windows due to the unix under-pinning, but with my Ubuntu machine, it’s just easier with GRASS, R, etc…

Tom

···

On Fri, Dec 28, 2012 at 11:03 AM, Daniel Lee <lee@isi-solutions.org> wrote:

Hi Paul,

I think one of your problems is… using windows :wink: I have heard that the Windows version of GRASS works a LOT better than it used to, but GRASS was actually the reason I switched to Linux a couple of years ago. Back then it just ran better in Linux - a lot better. Since then, I’ve never gone back to Windows because I’m very satisfied with Linux, not just with GRASS but with everything else I do with the computer. Of course, Linux vs. Windows is a whole different story and doesn’t belong in this list, but that was my experience.

If you’re wanting to use GRASS in a headless Ubuntu server anyway, why don’t you set up a Linux machine or at least a Linux installation in a virtual machine and play around with it there? There everything should work well and the development environment would match your production environment. OSGeo has a great live installation including all of the latest Geo software, Python, etc. - everything the;heart could desire. since I’m out and about at the moment I can’t send you the address, but just Google for an OSGeo live installation and you’ll see it right away.

Hope that helps,
Daniel

Am 28.12.2012 15:28 schrieb “Paul Meems” <bontepaarden@gmail.com>:

Hi Sotiris,

Thanks for your help.

I will have a look at the r.series.

Meanwhile I’ve discovered the graphical modeler. It is not working 100% in all cases but it does generates a Python script with all the necessary parameters.

This is my script so far, which seems to be working:
for x in range(1, 10, 1):
print “Working on day %d” % (x)

Create radiation for each day:

glob_rad = ‘global’ + str(x)
grass.run_command(‘r.sun’, flags = ‘s’, overwrite = True, elevin = ‘w001001@temp’, aspin = ‘aspect@temp’, slopein = ‘slope@temp’, glob_rad = glob_rad, day = x)

Combine the radiation file with the previous one:

if x == 2:
grass.run_command(“r.mapcalculator”, overwrite = True, amap = “global1”, bmap = “global2”, formula = “A+B”,
outfile = “suntemp2”)
elif x > 2:

Use temp name or else it won’t work:

amap = “suntemp” + str(x-1)
bmap = “global” + str(x) + “@temp”
outfile = “suntemp” + str(x)
grass.run_command(“r.mapcalculator”, overwrite = True, amap = amap, bmap = bmap, formula = “A+B”,
outfile = outfile)

Finalize:

grass.mapcalc(‘sun=’ + outfile, quiet=False, verbose=True, overwrite=True)

Clean up:

grass.run_command(‘g.mremove’, flags = ‘f’, rast = “suntemp*”)
grass.run_command(‘g.mremove’, flags = ‘f’, rast = “global*”)
print “Done”

Thanks

grass-user mailing list
grass-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-user

grass-user mailing list
grass-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-user

–

Thomas E Adams

Development & Operations Hydrologist
National Weather Service
Ohio River Forecast Center
1901 South State Route 134
Wilmington, OH 45177

[http://www.erh.noaa.gov/er/ohrfc/](http://www.erh.noaa.gov/er/ohrfc/)

EMAIL:	[thomas.adams@noaa.gov](mailto:thomas.adams@noaa.gov)
 
VOICE:	937-383-0528
FAX:	937-383-0033

Paul

2012/12/28 S. Koukoulas (lists) <sotkouklistes@gmail.com>

Dear Paul,

having said all that for r.mapcalc, I wonder whether you really need
mapcalc. In your case,
couldn’t you just use the * r.series * command with Sum (and perhaps
g.mlist can help you make a list of all the daily maps).

I think that it might be faster as well.
best,
sotiris

On 12/28/2012 03:08 PM, Paul Meems wrote:

Thanks Sotiris,

I’ve tried your suggestion but converted it to Python because I’m on
Windows.
This is my script:
grass.run_command(‘g.mremove’, rast = (‘out*’))
grass.mapcalc(‘sun=global1’, quiet=False, verbose=False, overwrite=True)
for x in range(2, 10, 1):
exp = ‘out=sun+global’ + str(x)
print exp
grass.mapcalc(exp, quiet=False, verbose=False, overwrite=True)
grass.run_command(‘g.rename’, flag=‘o’, rast = (‘out’,‘sun’))

This doesn’t result in the expected outcome.
sun is equal to global1 and no values are added
out is global1+global2 but is no more values are added. But mapcalc is
called several times.
I’ve tested this with:
r.what --v -f -n input=global1 east_north=156287.225281,383024.737026
r.what --v -f -n input=sun east_north=156287.225281,383024.737026
r.what --v -f -n input=out east_north=156287.225281,383024.737026

Not only am I a new user to GRASS but I’m also still a novice in
Python. Most likely it is something in my script.

If somebody has a different approach to get the solar radiation of a
whole year I’m happy to try that.

Thanks,

Paul

Date: Fri, 28 Dec 2012 14:36:15 +0200
From: “S. Koukoulas (lists)” <sotkouklistes@gmail.com

mailto:[sotkouklistes@gmail.com](mailto:sotkouklistes@gmail.com)>
To: grass-user@lists.osgeo.org mailto:[grass-user@lists.osgeo.org](mailto:grass-user@lists.osgeo.org)

Subject: Re: [GRASS-user] Grass, Python, mapcalc

Message-ID: <50DD923F.806@gmail.com mailto:[50DD923F.806@gmail.com](mailto:50DD923F.806@gmail.com)>

Content-Type: text/plain; charset=windows-1252

To my experience with r.mapcalc you cannot do what yo do with
programming languages… e.g. i=i+1 will not work directly.
Instead you
could try a more indirect way, something like (here is an example with
bash shell script):

#g.mremove rast=out* (to remove previous stuff, if needed)
r.mapcalc sun=global1
for a in ?seq 2 10?; do
r.mapcalc out = sun + global$a
g.rename --o rast=out,sun
done

basically the main idea is to use an intermediate map and then before
the loop ends, pass it (with g.rename) to the map variable you want.
There might be a more elegant way with python, but hopefully this
shell
script example might help you.
HTH,
sotiris

grass-user mailing list
grass-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-user

7

I understand I should use GRASS with Ubuntu to get the best results, but I’m not only new with GRASS and Python but also with Ubuntu :wink:

Ubuntu server I know a little and I have learned to appreciate it very much, but Ubuntu desktop is completely new for me.

That is the reason I wanted to start on Window, because I feel more comfortable with it.

It seems getting the annual solar radiation is working now. I need to update my script for using r.series.

I’m going to run a full year now. I have the ArcMap results for the same area as well and I first want to compare those.

After that I’m going to look at the rest of the ArcMap model, since the solar radiation is only one of the steps I need to convert to GRASS/Python.

When I have reproduced all steps in GRASS I’m going to create a Python script of it and then I can run the complete area on my Ubuntu server.

Thanks all for now and I will be back :wink:

···

Paul

Paul Meems
Release manager, configuration manager
and forum moderator of MapWindow GIS.
www.mapwindow.org

Owner of MapWindow.nl - Support for
Dutch speaking users.
www.mapwindow.nl

2012/12/28 Daniel Lee <lee@isi-solutions.org>

Hi Paul,

I think one of your problems is… using windows :wink: I have heard that the Windows version of GRASS works a LOT better than it used to, but GRASS was actually the reason I switched to Linux a couple of years ago. Back then it just ran better in Linux - a lot better. Since then, I’ve never gone back to Windows because I’m very satisfied with Linux, not just with GRASS but with everything else I do with the computer. Of course, Linux vs. Windows is a whole different story and doesn’t belong in this list, but that was my experience.

If you’re wanting to use GRASS in a headless Ubuntu server anyway, why don’t you set up a Linux machine or at least a Linux installation in a virtual machine and play around with it there? There everything should work well and the development environment would match your production environment. OSGeo has a great live installation including all of the latest Geo software, Python, etc. - everything the;heart could desire. since I’m out and about at the moment I can’t send you the address, but just Google for an OSGeo live installation and you’ll see it right away.

Hope that helps,
Daniel

Am 28.12.2012 15:28 schrieb “Paul Meems” <bontepaarden@gmail.com>:

Hi Sotiris,

Thanks for your help.

I will have a look at the r.series.

Meanwhile I’ve discovered the graphical modeler. It is not working 100% in all cases but it does generates a Python script with all the necessary parameters.

This is my script so far, which seems to be working:
for x in range(1, 10, 1):
print “Working on day %d” % (x)

Create radiation for each day:

glob_rad = ‘global’ + str(x)
grass.run_command(‘r.sun’, flags = ‘s’, overwrite = True, elevin = ‘w001001@temp’, aspin = ‘aspect@temp’, slopein = ‘slope@temp’, glob_rad = glob_rad, day = x)

Combine the radiation file with the previous one:

if x == 2:
grass.run_command(“r.mapcalculator”, overwrite = True, amap = “global1”, bmap = “global2”, formula = “A+B”,
outfile = “suntemp2”)
elif x > 2:

Use temp name or else it won’t work:

amap = “suntemp” + str(x-1)
bmap = “global” + str(x) + “@temp”
outfile = “suntemp” + str(x)
grass.run_command(“r.mapcalculator”, overwrite = True, amap = amap, bmap = bmap, formula = “A+B”,
outfile = outfile)

Finalize:

grass.mapcalc(‘sun=’ + outfile, quiet=False, verbose=True, overwrite=True)

Clean up:

grass.run_command(‘g.mremove’, flags = ‘f’, rast = “suntemp*”)
grass.run_command(‘g.mremove’, flags = ‘f’, rast = “global*”)
print “Done”

Thanks

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Paul

2012/12/28 S. Koukoulas (lists) <sotkouklistes@gmail.com>

Dear Paul,

having said all that for r.mapcalc, I wonder whether you really need
mapcalc. In your case,
couldn’t you just use the * r.series * command with Sum (and perhaps
g.mlist can help you make a list of all the daily maps).

I think that it might be faster as well.
best,
sotiris

On 12/28/2012 03:08 PM, Paul Meems wrote:

Thanks Sotiris,

I’ve tried your suggestion but converted it to Python because I’m on
Windows.
This is my script:
grass.run_command(‘g.mremove’, rast = (‘out*’))
grass.mapcalc(‘sun=global1’, quiet=False, verbose=False, overwrite=True)
for x in range(2, 10, 1):
exp = ‘out=sun+global’ + str(x)
print exp
grass.mapcalc(exp, quiet=False, verbose=False, overwrite=True)
grass.run_command(‘g.rename’, flag=‘o’, rast = (‘out’,‘sun’))

This doesn’t result in the expected outcome.
sun is equal to global1 and no values are added
out is global1+global2 but is no more values are added. But mapcalc is
called several times.
I’ve tested this with:
r.what --v -f -n input=global1 east_north=156287.225281,383024.737026
r.what --v -f -n input=sun east_north=156287.225281,383024.737026
r.what --v -f -n input=out east_north=156287.225281,383024.737026

Not only am I a new user to GRASS but I’m also still a novice in
Python. Most likely it is something in my script.

If somebody has a different approach to get the solar radiation of a
whole year I’m happy to try that.

Thanks,

Paul

Date: Fri, 28 Dec 2012 14:36:15 +0200
From: “S. Koukoulas (lists)” <sotkouklistes@gmail.com

mailto:[sotkouklistes@gmail.com](mailto:sotkouklistes@gmail.com)>
To: grass-user@lists.osgeo.org mailto:[grass-user@lists.osgeo.org](mailto:grass-user@lists.osgeo.org)

Subject: Re: [GRASS-user] Grass, Python, mapcalc

Message-ID: <50DD923F.806@gmail.com mailto:[50DD923F.806@gmail.com](mailto:50DD923F.806@gmail.com)>

Content-Type: text/plain; charset=windows-1252

To my experience with r.mapcalc you cannot do what yo do with
programming languages… e.g. i=i+1 will not work directly.
Instead you
could try a more indirect way, something like (here is an example with
bash shell script):

#g.mremove rast=out* (to remove previous stuff, if needed)
r.mapcalc sun=global1
for a in ?seq 2 10?; do
r.mapcalc out = sun + global$a
g.rename --o rast=out,sun
done

basically the main idea is to use an intermediate map and then before
the loop ends, pass it (with g.rename) to the map variable you want.
There might be a more elegant way with python, but hopefully this
shell
script example might help you.
HTH,
sotiris

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