Re: [GRASS-user] zonal statistics for multiple areas
I was trying with nested loops and it seems not to be working. Now I tried
again (more carefully i have to say) and it worked! Thanks to everybody!
Il giorno mer 31 ott 2018 alle ore 21:55 Micha Silver
ha scritto:
>
> On 10/31/18 11:59 AM, Alessandro Sebastiani wrote:
> > Dear all, i was able to compute zonal statistics for multiple areas
> > using this script. I used
> > > import grass.script as gscript
> > > v_list = gscript.read_command("g.list" , type =
> > "vect").strip().split("\n")
> > # i have 5 vectors in my list
> > > method = ("sum" , "average")
> > > for v in v_list:
> > >gscript.run_command("v.rast.stats", map_=v, raster = "LC1",
> > column_prefix = "LC1", method = methods)
> >
> > Now i have like 4 rasters that i would like to use as input to compute
> > my statistics. Is there a way to loop this process for rasters and
> > vector at the same time? i tried creating a list for rasters and using
> > the name list as raster input but it seems not to work! cheers,
> Alessandro
>
>
> What exactly did you try? There should not be any problem to do nested
> loops. i.e.:
>
>
> import grass.script as gscript
>
> v_list = gscript.read_command("g.list" , type = "vect").strip().split("\n")
> # i have 5 vectors in my list
> r_list = gscript.read_command("g.list" , type = "rast",
> pattern="LC*").strip().split("\n")
> method = ("sum" , "average")
> for v in v_list:
> for r in r_list:
> gscript.run_command("v.rast.stats",
> map_=v, raster = r, column_prefix = r, method = methods)
>
>
> >
> > Il giorno mar 30 ott 2018 alle ore 11:52 Alessandro Sebastiani
> > > > ha scritto:
> >
> > Thanks a lot for your help!
> >
> > Il giorno mar 30 ott 2018 alle ore 11:49 Nikos Alexandris
> > mailto:n...@nikosalexandris.net>> ha
> scritto:
> >
> > * Alessandro Sebastiani > > [2018-10-29
> > 21:32:51 +0100]:
> >
> > >thank you all for your suggestions.
> > >Dear Nikos, I have some 0-1 rasters that represents
> > presence-absence of
> > >different land covers. Each raster's resolution is 10x10m,
> > thus i want to
> > >compute the sum in order to obtain the surface covered by
> > each land cover
> > >within my buffers. As regards to the buffer, i want to use
> > the 0-100,
> > >0-200, 0-300, 0-400 and 0-500 for computing stats. I can do
> > it separately
> > >with the module v.rast.stats. I just don't know how to loop
> > it in a python
> > >script
> >
> > Dear Alessandro,
> >
> > I don't have time to write back as I would like. Instead, I
> > will send
> > you off-list some unpublished script. With a bit of reading,
> > there, you
> > might identify some ideas that will eventually help in what
> > you are
> > doing.
> >
> > Kind regards, Nikos
> >
> >
> > ___
> > grass-user mailing list
> > grass-user@lists.osgeo.org
> > https://lists.osgeo.org/mailman/listinfo/grass-user
>
> --
> Micha Silver
> Ben Gurion Univ.
> Sde Boker, Remote Sensing Lab
> cell: +972-523-665918
>
>
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Re: [GRASS-user] zonal statistics for multiple areas
On 10/31/18 11:59 AM, Alessandro Sebastiani wrote:
Dear all, i was able to compute zonal statistics for multiple areas
using this script. I used
> import grass.script as gscript
> v_list = gscript.read_command("g.list" , type =
"vect").strip().split("\n")
# i have 5 vectors in my list
> method = ("sum" , "average")
> for v in v_list:
> gscript.run_command("v.rast.stats", map_=v, raster = "LC1",
column_prefix = "LC1", method = methods)
Now i have like 4 rasters that i would like to use as input to compute
my statistics. Is there a way to loop this process for rasters and
vector at the same time? i tried creating a list for rasters and using
the name list as raster input but it seems not to work! cheers, Alessandro
What exactly did you try? There should not be any problem to do nested
loops. i.e.:
import grass.script as gscript
v_list = gscript.read_command("g.list" , type = "vect").strip().split("\n")
# i have 5 vectors in my list
r_list = gscript.read_command("g.list" , type = "rast",
pattern="LC*").strip().split("\n")
method = ("sum" , "average")
for v in v_list:
for r in r_list:
gscript.run_command("v.rast.stats",
map_=v, raster = r, column_prefix = r, method = methods)
Il giorno mar 30 ott 2018 alle ore 11:52 Alessandro Sebastiani
> ha scritto:
Thanks a lot for your help!
Il giorno mar 30 ott 2018 alle ore 11:49 Nikos Alexandris
mailto:n...@nikosalexandris.net>> ha scritto:
* Alessandro Sebastiani mailto:alessandro.sebasti...@uniroma1.it>> [2018-10-29
21:32:51 +0100]:
>thank you all for your suggestions.
>Dear Nikos, I have some 0-1 rasters that represents
presence-absence of
>different land covers. Each raster's resolution is 10x10m,
thus i want to
>compute the sum in order to obtain the surface covered by
each land cover
>within my buffers. As regards to the buffer, i want to use
the 0-100,
>0-200, 0-300, 0-400 and 0-500 for computing stats. I can do
it separately
>with the module v.rast.stats. I just don't know how to loop
it in a python
>script
Dear Alessandro,
I don't have time to write back as I would like. Instead, I
will send
you off-list some unpublished script. With a bit of reading,
there, you
might identify some ideas that will eventually help in what
you are
doing.
Kind regards, Nikos
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--
Micha Silver
Ben Gurion Univ.
Sde Boker, Remote Sensing Lab
cell: +972-523-665918
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Re: [GRASS-user] zonal statistics for multiple areas
Dear all, i was able to compute zonal statistics for multiple areas using
this script. I used
> import grass.script as gscript
> v_list = gscript.read_command("g.list" , type =
"vect").strip().split("\n")
# i have 5 vectors in my list
> method = ("sum" , "average")
> for v in v_list:
>gscript.run_command("v.rast.stats", map_=v, raster = "LC1",
column_prefix = "LC1", method = methods)
Now i have like 4 rasters that i would like to use as input to compute my
statistics. Is there a way to loop this process for rasters and vector at
the same time? i tried creating a list for rasters and using the name list
as raster input but it seems not to work! cheers, Alessandro
Il giorno mar 30 ott 2018 alle ore 11:52 Alessandro Sebastiani <
alessandro.sebasti...@uniroma1.it> ha scritto:
> Thanks a lot for your help!
>
> Il giorno mar 30 ott 2018 alle ore 11:49 Nikos Alexandris <
> n...@nikosalexandris.net> ha scritto:
>
>> * Alessandro Sebastiani [2018-10-29
>> 21:32:51 +0100]:
>>
>> >thank you all for your suggestions.
>> >Dear Nikos, I have some 0-1 rasters that represents presence-absence of
>> >different land covers. Each raster's resolution is 10x10m, thus i want to
>> >compute the sum in order to obtain the surface covered by each land cover
>> >within my buffers. As regards to the buffer, i want to use the 0-100,
>> >0-200, 0-300, 0-400 and 0-500 for computing stats. I can do it separately
>> >with the module v.rast.stats. I just don't know how to loop it in a
>> python
>> >script
>>
>> Dear Alessandro,
>>
>> I don't have time to write back as I would like. Instead, I will send
>> you off-list some unpublished script. With a bit of reading, there, you
>> might identify some ideas that will eventually help in what you are
>> doing.
>>
>> Kind regards, Nikos
>>
>
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Re: [GRASS-user] zonal statistics for multiple areas
Thanks a lot for your help! Il giorno mar 30 ott 2018 alle ore 11:49 Nikos Alexandris < n...@nikosalexandris.net> ha scritto: > * Alessandro Sebastiani [2018-10-29 > 21:32:51 +0100]: > > >thank you all for your suggestions. > >Dear Nikos, I have some 0-1 rasters that represents presence-absence of > >different land covers. Each raster's resolution is 10x10m, thus i want to > >compute the sum in order to obtain the surface covered by each land cover > >within my buffers. As regards to the buffer, i want to use the 0-100, > >0-200, 0-300, 0-400 and 0-500 for computing stats. I can do it separately > >with the module v.rast.stats. I just don't know how to loop it in a python > >script > > Dear Alessandro, > > I don't have time to write back as I would like. Instead, I will send > you off-list some unpublished script. With a bit of reading, there, you > might identify some ideas that will eventually help in what you are > doing. > > Kind regards, Nikos > ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] zonal statistics for multiple areas
* Alessandro Sebastiani [2018-10-29 21:32:51 +0100]: thank you all for your suggestions. Dear Nikos, I have some 0-1 rasters that represents presence-absence of different land covers. Each raster's resolution is 10x10m, thus i want to compute the sum in order to obtain the surface covered by each land cover within my buffers. As regards to the buffer, i want to use the 0-100, 0-200, 0-300, 0-400 and 0-500 for computing stats. I can do it separately with the module v.rast.stats. I just don't know how to loop it in a python script Dear Alessandro, I don't have time to write back as I would like. Instead, I will send you off-list some unpublished script. With a bit of reading, there, you might identify some ideas that will eventually help in what you are doing. Kind regards, Nikos signature.asc Description: PGP signature ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] zonal statistics for multiple areas
Resending, as I forgot to Cc the list. * Alessandro Sebastiani [2018-10-29 16:05:54 +0100]: Hello to everybody,o Hello Alessandro, I hope my question is appropriate for this mail list. I have created 5 different buffer layers (d=100,200,300,400,500 m) from a point vector. Now i want to compute some zonal statistics using different rasters as input. You are in the right place. And the first guess is that what you need to do is not difficult using GRASS GIS. Which rasters exactly? Would you want to use as base maps each of the '0 to 100 m', '100 to 200 m' and so on "buffers" or '0 to 100 m', '0 to 200 m' and so on up to '0 to 500 m'? And then, the 'other' maps would be the 'cover' map, each time? If you share exactly what you need to do, i.e. in form of an algorithm using pseudo-syntax, it will be easier to understand and potentially suggest ways to get this done. For example: ``` for each Buffer in Buffers: compute zonal statistics using base=Buffer and cover=RasterX ``` For example, you might be able to get part of this done using raster maps only and `r.mapcalc` expressions, without the need to construct many loops and require an extra step in the end to patch maps together. I know how to do that separately, but i was wondering how could i automate this procedure using a python script. If you write down the way to do it separately, then you are just few steps away in looping over your input rasters. The key point is, obviously, to express what is to be done in an unambiguous way. I know python's basics, but i was not able to do so following guidelines that i found on the internet, e.g GRASS tutorial. Please share which guidelines, i.e. which GRASS GIS tutorial you refer to. Nikos signature.asc Description: PGP signature ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] zonal statistics for multiple areas
thank you all for your suggestions.
Dear Nikos, I have some 0-1 rasters that represents presence-absence of
different land covers. Each raster's resolution is 10x10m, thus i want to
compute the sum in order to obtain the surface covered by each land cover
within my buffers. As regards to the buffer, i want to use the 0-100,
0-200, 0-300, 0-400 and 0-500 for computing stats. I can do it separately
with the module v.rast.stats. I just don't know how to loop it in a python
script
Dear Stefan, thank you, i guess that using multiple rasters as input would
be a good solution. however i would really like to loop it using a python
script since that would be useful in other situation that i'm going to face
in the next days
Dear Micha thank you, i'll try ASAP!
Il giorno lun 29 ott 2018 alle ore 21:07 Micha Silver
ha scritto:
> Some further python specific tips that might help.
>
>
> To get a list of rasters that match some pattern (say you have many
> rasters like "band1", "band2",...), then run v.rast.stats on each of them
> in a loop to get zonal stats in the vector "buffers":
>
>
> # This must be run from within a grass session
>
> import grass.script as gscript
>
> rast_list = gscript.read_command("g.list", type = "rast", pattern =
> "band*").strip().split("\n")
>
> # Loop thru the rasters, run v.rast.stats, and specify the column prefix
> using the raster name.
>
> methods = ("minimum", "maximum", "average", "sum") # add whatever stats
> you need
>
> for r in rast_list:
>
> gscript.run_command("v.rast.stats",
>
> map_ = "buffers", raster=r, column_prefix=r, method=methods)
>
>
>
> Be aware that if you have many rasters, you'll end up with many,many
> columns in the "buffers" vector
>
>
>
> On 10/29/18 9:54 PM, Stefan Blumentrath wrote:
>
> Hi Alessandro,
>
>
>
> You could try v.rast.bufferstats [1], if you do not have hundrets of
> thousands of points….
>
>
>
> If the buffers don`t overlap, you could use v.rast.stats [2] from the
> upcoming GRASS 7.6 release, that will allow multiple raster input…
>
>
>
> Otherwise have a look at the general introduction to GRASS and Python [3].
>
>
>
> Cheers
>
> Stefan
>
>
>
> 1: https://grass.osgeo.org/grass74/manuals/addons/v.rast.bufferstats.html
>
> 2: https://grass.osgeo.org/grass76/manuals/v.rast.stats.html
>
> 3: https://grasswiki.osgeo.org/wiki/GRASS_and_Python
>
>
>
>
>
> *From:* grass-user
> *On Behalf Of *Alessandro Sebastiani
> *Sent:* mandag 29. oktober 2018 16:06
> *To:* grass-user@lists.osgeo.org
> *Subject:* [GRASS-user] zonal statistics for multiple areas
>
>
>
> Hello to everybody,
>
> I hope my question is appropriate for this mail list. I have created 5
> different buffer layers (d=100,200,300,400,500 m) from a point vector. Now
> i want to compute some zonal statistics using different rasters as input. I
> know how to do that separately, but i was wondering how could i automate
> this procedure using a python script. I know python's basics, but i was not
> able to do so following guidelines that i found on the internet, e.g GRASS
> tutorial. Thank you in advance, A
>
> ___
> grass-user mailing
> listgrass-user@lists.osgeo.orghttps://lists.osgeo.org/mailman/listinfo/grass-user
>
> --
> Micha Silver
> Ben Gurion Univ.
> Sde Boker, Remote Sensing Lab
> cell: +972-523-665918
>
>
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Re: [GRASS-user] zonal statistics for multiple areas
Some further python specific tips that might help.
To get a list of rasters that match some pattern (say you have
many rasters like "band1", "band2",...), then run v.rast.stats on
each of them in a loop to get zonal stats in the vector "buffers":
# This must be run from within a grass
session
import grass.script as gscript
rast_list = gscript.read_command("g.list",
type = "rast", pattern = "band*").strip().split("\n")
# Loop thru the rasters, run v.rast.stats,
and specify the column prefix using the raster name.
methods = ("minimum", "maximum", "average",
"sum") # add whatever stats you need
for r in rast_list:
gscript.run_command("v.rast.stats",
map_ = "buffers", raster=r,
column_prefix=r, method=methods)
Be aware that if you have many rasters, you'll end up with
many,many columns in the "buffers" vector
On 10/29/18 9:54 PM, Stefan Blumentrath
wrote:
Hi
Alessandro,
You could try v.rast.bufferstats [1], if you do
not have hundrets of thousands of points….
If the buffers don`t overlap, you could use
v.rast.stats [2] from the upcoming GRASS 7.6 release, that
will allow multiple raster input…
Otherwise have a look at the general
introduction to GRASS and Python [3].
Cheers
Stefan
1:
https://grass.osgeo.org/grass74/manuals/addons/v.rast.bufferstats.html
2:
https://grass.osgeo.org/grass76/manuals/v.rast.stats.html
3:
https://grasswiki.osgeo.org/wiki/GRASS_and_Python
From: grass-user
On Behalf Of Alessandro Sebastiani
Sent: mandag 29. oktober 2018 16:06
To: grass-user@lists.osgeo.org
Subject: [GRASS-user] zonal statistics for multiple
areas
Hello to everybody,
I hope my question is appropriate for
this mail list. I have created 5 different buffer layers
(d=100,200,300,400,500 m) from a point vector. Now i want
to compute some zonal statistics using different rasters
as input. I know how to do that separately, but i was
wondering how could i automate this procedure using a
python script. I know python's basics, but i was not able
to do so following guidelines that i found on the
internet, e.g GRASS tutorial. Thank you in advance, A
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--
Micha Silver
Ben Gurion Univ.
Sde Boker, Remote Sensing Lab
cell: +972-523-665918
___
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Re: [GRASS-user] zonal statistics for multiple areas
Hi Alessandro, You could try v.rast.bufferstats [1], if you do not have hundrets of thousands of points…. If the buffers don`t overlap, you could use v.rast.stats [2] from the upcoming GRASS 7.6 release, that will allow multiple raster input… Otherwise have a look at the general introduction to GRASS and Python [3]. Cheers Stefan 1: https://grass.osgeo.org/grass74/manuals/addons/v.rast.bufferstats.html 2: https://grass.osgeo.org/grass76/manuals/v.rast.stats.html 3: https://grasswiki.osgeo.org/wiki/GRASS_and_Python From: grass-user On Behalf Of Alessandro Sebastiani Sent: mandag 29. oktober 2018 16:06 To: grass-user@lists.osgeo.org Subject: [GRASS-user] zonal statistics for multiple areas Hello to everybody, I hope my question is appropriate for this mail list. I have created 5 different buffer layers (d=100,200,300,400,500 m) from a point vector. Now i want to compute some zonal statistics using different rasters as input. I know how to do that separately, but i was wondering how could i automate this procedure using a python script. I know python's basics, but i was not able to do so following guidelines that i found on the internet, e.g GRASS tutorial. Thank you in advance, A ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] zonal statistics for multiple areas
Hello to everybody, I hope my question is appropriate for this mail list. I have created 5 different buffer layers (d=100,200,300,400,500 m) from a point vector. Now i want to compute some zonal statistics using different rasters as input. I know how to do that separately, but i was wondering how could i automate this procedure using a python script. I know python's basics, but i was not able to do so following guidelines that i found on the internet, e.g GRASS tutorial. Thank you in advance, A ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
