[GRASS-user] Re: grass-user Digest, Vol 47, Issue 52

Nathaniel_Iwuchukwu · March 29, 2010, 6:58am

Please what’s the procedure or commands for extrating road network from a raster map? i think i have been going round the circle with classofocation and rectification of image. i have used this commands but i don’t get any results:
i.group
i.composite
i.class
i.cluster
r.digit
i.maxlik
i.gensigset
nothing seems to get me the road network result i want.
Please i need help and i am running GRASS on Linux Ubuntu.
thanks.

On Mon, Mar 22, 2010 at 11:09 AM, <grass-user-request@lists.osgeo.org> wrote:

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Today’s Topics:

ERROR: G_malloc: unable to allocate 2147483648 bytes at
main.c:153 (ikechinedu@gmail.com)

Re: importing dem files: projection details? (Markus Neteler)

Re: ERROR: G_malloc: unable to allocate 2147483648 bytes at
main.c:153 (Hamish)

Re: make command (install add on) (schorschli)

Helpp needed to call Grass from inside Python Plugin
(Bishwarup Banerjee)

grass editing (Gary Nobles)

Re: ERROR: G_malloc: unable to allocate 2147483648 bytes at
main.c:153 (Glynn Clements)

Osgeo4W grass error (Pablo Carreira)

Message: 1
Date: Sun, 21 Mar 2010 13:02:00 -0700
From: ikechinedu@gmail.com
Subject: [GRASS-user] ERROR: G_malloc: unable to allocate 2147483648
bytes at main.c:153
To: grass-user@lists.osgeo.org
Message-ID:
<4529578.106556.1269201720004.JavaMail.root@jim.nabble.com>
Content-Type: text/plain; charset=us-ascii

Hi, i am trying extract road network from a raster map but each time i run the image filter, i get this error message: ERROR: G_malloc: unable to allocate 2147483648 bytes at main.c:153.

i also connnot use the i.class command on my windows machine which is the platform i am working with. please how can i extract a road network from raster map on windows platform?
thank you.
Nathaniel

Message: 2
Date: Mon, 22 Mar 2010 00:23:48 +0100
From: Markus Neteler <neteler@osgeo.org>
Subject: Re: [GRASS-user] importing dem files: projection details?
To: Tyler Smith <tyler.smith@eku.edu>
Cc: GRASS user list <grass-user@lists.osgeo.org>
Message-ID:
<86782b611003211623x6f777673t62a66fff6526f2d@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1

On Mon, Mar 15, 2010 at 7:38 PM, Tyler Smith <tyler.smith@eku.edu> wrote:

On 03/15/2010 09:38 AM, Markus Neteler wrote:

On Mon, Mar 15, 2010 at 1:35 PM, Tyler Smith<tyler.smith@eku.edu> wrote:

On 03/15/2010 03:42 AM, Markus Neteler wrote:

Trying the auto route:

grass64 -gui
select define new location with georeferenced file
select the dem file: k42.dem
select the TN transformation, as probably better than the default for
adjacent Kentucky
enter GRASS with the newly created location and the PERMANENT mapset

Results in this error:

“g.proj or projection error: ERROR: default region is invalid
line 3:<north: 1080:43:46N>”

So GRASS has automatically set up the location using degrees, and then
get
confused when the raster co-ordinates are provided in meters. Which
appears
to be fairly close to the sort of problem I ran into when setting this up
manually. What am I missing?

Please post the output of gdalinfo on that file. GRASS uses GDAL to detect
projections from metadata.

Markus

Thanks for help! Here it is:

gdalinfo k42.dem
Driver: USGSDEM/USGS Optional ASCII DEM (and CDED)
Files: k42.dem
Size is 1222, 1535
Coordinate System is:
GEOGCS[“NAD83”,
DATUM[“North_American_Datum_1983”,
SPHEROID[“GRS 1980”,6378137,298.257222101,
…
Metadata:
AREA_OR_POINT=Point
Corner Coordinates:

Upper Left ( 1467.054, 1080.729)
Lower Left ( 1467.054, 1067.938)
Upper Right ( 1477.237, 1080.729)
Lower Right ( 1477.237, 1067.938)
Center ( 1472.146, 1074.334)
…

I get actually a somewhat different result (GDAL trunk):

gdalinfo m40.dem
Driver: USGSDEM/USGS Optional ASCII DEM (and CDED)
Files: m40.dem
…
Corner Coordinates:
Upper Left ( 1447.317, 1055.177) (Invalid angle,Invalid angle)
Lower Left ( 1447.317, 1042.411) (Invalid angle,Invalid angle)
Upper Right ( 1457.509, 1055.177) (Invalid angle,Invalid angle)
Lower Right ( 1457.509, 1042.411) (Invalid angle,Invalid angle)
Center ( 1452.413, 1048.794) (Invalid angle,Invalid angle)
Band 1 Block=1223x1532 Type=Float32, ColorInterp=Undefined
NoData Value=-32767
Unit Type: ft

You may want to signal this as GDAL bug in the GDAL butracker:
http://trac.osgeo.org/gdal/

Unless GDAL doesn’t read it correctly, it won’t be understood by GRASS.
I tested with
ftp://ftp.kymartian.ky.gov/dems_usgs/m39.dem.zip

Markus

Message: 3
Date: Sun, 21 Mar 2010 22:41:12 -0700 (PDT)
From: Hamish <hamish_b@yahoo.com>
Subject: Re: [GRASS-user] ERROR: G_malloc: unable to allocate
2147483648 bytes at main.c:153
To: grass-user@lists.osgeo.org, ikechinedu@gmail.com
Message-ID: <373432.58091.qm@web110015.mail.gq1.yahoo.com>
Content-Type: text/plain; charset=us-ascii

Nathaniel wrote:

Hi, i am trying extract road network
from a raster map but each time i run the image filter, i
get this error message: ERROR: G_malloc: unable to allocate
2147483648 bytes at main.c:153.

aka it is trying to use >2gig RAM and there is not enough memory.
Possibly because you are not using a 64bit OS, and possibly because
you don’t actually have that much memory in your computer.
Maybe try on a smaller dataset?

i also connnot use the i.class command on my windows
machine which is the platform i am working with.

you will have to wait for someone to build GRASS 6.4.0RC6 for Cygwin.
i.class uses UNIX-style Xmonitors which are not available on standard
MS Windows. (or try GRASS on a Mac or Linux computer/virtual machine)

Hamish

Message: 4
Date: Mon, 22 Mar 2010 01:44:01 -0800 (PST)
From: schorschli <matthiasoswald@hotmail.com>
Subject: [GRASS-user] Re: make command (install add on)
To: grass-user@lists.osgeo.org
Message-ID: <1269251041185-4776893.post@n2.nabble.com>
Content-Type: text/plain; charset=us-ascii

Thanks for answering.

Are you sure about this directory?

MODULE_TOPDIR should point to the GRASS installation directory which
contains bin/, lib/ and other GRASS stuff.

Yes, the directory is the one containing the grass-folders (bin/, lib/ and
others).

I could solve this problem. It was not a wrong MODULE_TOPDIR path, but wrong
extensions for the makefiles.

Now I can run the make command. But this is resulting in hunderts of errors
and warning. Here is a printscreen of the first couple of lignes in the
console…

http://n2.nabble.com/file/n4776893/errors.png
http://n2.nabble.com/file/n4776893/errors.png errors.png

So maybe its better to just give it up with the addons…

–
View this message in context: http://n2.nabble.com/make-command-install-add-on-tp4764072p4776893.html
Sent from the Grass - Users mailing list archive at Nabble.com.

Message: 5
Date: Mon, 22 Mar 2010 17:58:42 +0530
From: Bishwarup Banerjee <bishwarup.banerjee@gmail.com>
Subject: [GRASS-user] Helpp needed to call Grass from inside Python
Plugin
To: GRASS developers list <grass-dev@lists.osgeo.org>,
grass-user@lists.osgeo.org
Message-ID:
<78e951a61003220528o10e648a6m2fbd3c878a2897a2@mail.gmail.com>
Content-Type: text/plain; charset=“iso-8859-1”

Hi All,

I want to call the grass functionalities from inside my python plugins, in
QGIS
For example: the Grass’s raster to polygon script, with out going inside the
grass plugin.
Can I set the Grass Mapset, and location from inside my python plugin?
Is this possible?
my configurations are:
QGIS 0.11, GRASS 6.3, python 2.5, Windows

Thank you in advance
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Message: 6
Date: Mon, 22 Mar 2010 03:10:42 -0800 (PST)
From: Gary Nobles <garynobles@yahoo.com>
Subject: [GRASS-user] grass editing
To: grass-user@lists.osgeo.org
Message-ID: <1269256242668-4777030.post@n2.nabble.com>
Content-Type: text/plain; charset=us-ascii

Hi, I have been editing a grass point dataset in qgis unfortunately I have
just added 400 centroids rather than points! Is there anyway to delete just
the centroids?

Thanks

Gary

View this message in context: http://n2.nabble.com/grass-editing-tp4777030p4777030.html
Sent from the Grass - Users mailing list archive at Nabble.com.

Message: 7
Date: Mon, 22 Mar 2010 13:54:49 +0000
From: Glynn Clements <glynn@gclements.plus.com>
Subject: Re: [GRASS-user] ERROR: G_malloc: unable to allocate
2147483648 bytes at main.c:153
To: Hamish <hamish_b@yahoo.com>
Cc: grass-user@lists.osgeo.org, ikechinedu@gmail.com
Message-ID: <19367.30377.130266.683319@cerise.gclements.plus.com>
Content-Type: text/plain; charset=us-ascii

Hamish wrote:

Hi, i am trying extract road network
from a raster map but each time i run the image filter, i
get this error message: ERROR: G_malloc: unable to allocate
2147483648 bytes at main.c:153.

aka it is trying to use >2gig RAM and there is not enough memory.
Possibly because you are not using a 64bit OS, and possibly because
you don’t actually have that much memory in your computer.
Maybe try on a smaller dataset?

2147483648 is exactly 2GiB; I’m wondering if that’s the actual size
(e.g. 16384 x 16384 x 8bytes/cell) or an uninitialised variable (e.g.
initialised to INT_MIN in the code and not updated).

On Linux, it is possible to allocate 2GiB on a 32-bit system, provided
that there’s a contiguous block (in practice, this means that the
stack size isn’t “unlimited”). You don’t need that much physical RAM,
only swap (although performance may be unacceptable if you’re relying
upon swap; it depends upon the access pattern).

“Desktop” versions of Windows normally only allow 2GiB on 32-bit
systems. Server versions allow up to 3GiB, and the desktop versions
can be tweaked to allow it (but it isn’t straightforward).

i also connnot use the i.class command on my windows
machine which is the platform i am working with.

you will have to wait for someone to build GRASS 6.4.0RC6 for Cygwin.
i.class uses UNIX-style Xmonitors which are not available on standard
MS Windows. (or try GRASS on a Mac or Linux computer/virtual machine)

I’ll probably be building RC6 for Cygwin some time today.

–
Glynn Clements <glynn@gclements.plus.com>

Message: 8
Date: Mon, 22 Mar 2010 12:03:01 -0300
From: Pablo Carreira <pablotcarreira@hotmail.com>
Subject: [GRASS-user] Osgeo4W grass error
To: <grass-user@lists.osgeo.org>
Message-ID: SNT114-W54FC77CFFE5D19331A6E4BD6270@phx.gbl
Content-Type: text/plain; charset=“utf-8”

Hi, I’am trying to start the latest osgeo4w grass on windows 7 but I get an error when I select the dataset. Is it about the language? How can I start grass in english and not in portuguese?

Regards,
Pablo.

Here is the error:

C:>“C:\OSGeo4W\apps\grass\grass-6.4.0svn”\etc\init.bat -wxpython access: Invalid argument
ERRO:LOCAÃƒâ”œO << C:\teste/ >> indisponÃ vel
Traceback (most recent call last):
File “C:/OSGeo4W/apps/grass/grass-6.4.0svn/etc/wxpython/gis_set.py”, line 853,
in
GRASSStartUp = StartUp(0)
File “C:\OSGeo4W\apps\Python25\lib\site-packages\wx-2.8-msw-unicode\wx_core.p
y”, line 7935, in init
self._BootstrapApp()
File “C:\OSGeo4W\apps\Python25\lib\site-packages\wx-2.8-msw-unicode\wx_core.p
y”, line 7509, in _BootstrapApp
return core.PyApp__BootstrapApp(*args, **kwargs)
File “C:/OSGeo4W/apps/grass/grass-6.4.0svn/etc/wxpython/gis_set.py”, line 824,
in OnInit
StartUp = GRASSStartup()
File “C:/OSGeo4W/apps/grass/grass-6.4.0svn/etc/wxpython/gis_set.py”, line 165,
in init
self._set_properties()
File “C:/OSGeo4W/apps/grass/grass-6.4.0svn/etc/wxpython/gis_set.py”, line 206,
in _set_properties
self.OnSetDatabase(None)
File “C:/OSGeo4W/apps/grass/grass-6.4.0svn/etc/wxpython/gis_set.py”, line 664,
in OnSetDatabase
self.OnSelectLocation(None)
File “C:/OSGeo4W/apps/grass/grass-6.4.0svn/etc/wxpython/gis_set.py”, line 616,
in OnSelectLocation
self.listOfLocations[self.lblocations.GetSelection()]))
File “C:/OSGeo4W/apps/grass/grass-6.4.0svn/etc/wxpython/gis_set.py”, line 584,
in UpdateMapsets
stderr=None)
File “C:\OSGeo4W\apps\grass\grass-6.4.0svn\etc\wxpython\gui_modules\gcmd.py”,
line 356, in init
_("Error: ") + self.GetError()))
File “C:\OSGeo4W\apps\grass\grass-6.4.0svn\etc\wxpython\gui_modules\gcmd.py”,
line 449, in GetError
return unicode(msg, “utf-8”)
UnicodeDecodeError: ‘utf8’ codec can’t decode bytes in position 4-5: invalid dat
a

Navegue sem medo com o Internet Explorer 8. Clique aqui para instalar gratuitamente.
http://go.microsoft.com/?linkid=9707132
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End of grass-user Digest, Vol 47, Issue 52

neteler · March 29, 2010, 8:38am

On Mon, Mar 29, 2010 at 8:58 AM, Nathaniel Iwuchukwu
<ikechinedu@gmail.com> wrote:

Please what's the procedure or commands for extrating road network from a
raster map? i think i have been going round the circle with classofocation
and rectification of image. i have used this commands but i don't get any
results:
i.group
i.composite
i.class
i.cluster
r.digit
i.maxlik
i.gensigset
nothing seems to get me the road network result i want.
Please i need help and i am running GRASS on Linux Ubuntu.
thanks.

1. r.thin: thinning of lines
2. r.to.vect: generate vector lines

Markus

Micha_Silver · March 29, 2010, 8:58am

Nathaniel:

Nathaniel Iwuchukwu wrote:

Please what's the procedure or commands for extrating road network from a raster map? i think i have been going round the circle with classofocation and rectification of image. i have used this commands

Hope you didn't mean "class-suffocation"

but i don't get any results:
i.group
i.composite
i.class
i.cluster
r.digit
i.maxlik
i.gensigset
nothing seems to get me the road network result i want.

What kind of raster are we talking about? If this is a scanned topo map, with the roads symbolized by a certain color, then you might be able to get started with a simple r.mapcalc. First identify the exact value of the pixels of the road, then something like:
r.mapcalc road_rast="if( raster_map=<road_pixel_value>, 1, null() )
then do:
r.thin road_rast out=road_rast_thin
r.to.vect road_rast_thin type=line out=road_vect

Note: this won't get you a road "network", just a line vector. Creating a proper network is another process.
Note 2: If you're working with an aerial photo, then the above won't do you any good. In that case you will have to try some procedure of image classification. And then you'll have to deal with the problem you mentioned previously of running out of memory... Either more RAM in the computer, or a smaller region, or a larger resolution.

Please i need help and i am running GRASS on Linux Ubuntu.
thanks.

On Mon, Mar 22, 2010 at 11:09 AM, <grass-user-request@lists.osgeo.org <mailto:grass-user-request@lists.osgeo.org>> wrote:

    Send grass-user mailing list submissions to
           grass-user@lists.osgeo.org <mailto:grass-user@lists.osgeo.org>

    To subscribe or unsubscribe via the World Wide Web, visit
           http://lists.osgeo.org/mailman/listinfo/grass-user
    or, via email, send a message with subject or body 'help' to
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    <mailto:grass-user-request@lists.osgeo.org>

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    When replying, please edit your Subject line so it is more specific
    than "Re: Contents of grass-user digest..."

    Today's Topics:

      1. ERROR: G_malloc: unable to allocate 2147483648 bytes at
         main.c:153 (ikechinedu@gmail.com <mailto:ikechinedu@gmail.com>)
      2. Re: importing dem files: projection details? (Markus Neteler)
      3. Re: ERROR: G_malloc: unable to allocate 2147483648 bytes at
         main.c:153 (Hamish)
      4. Re: make command (install add on) (schorschli)
      5. Helpp needed to call Grass from inside Python Plugin
         (Bishwarup Banerjee)
      6. grass editing (Gary Nobles)
      7. Re: ERROR: G_malloc: unable to allocate 2147483648 bytes at
         main.c:153 (Glynn Clements)
      8. Osgeo4W grass error (Pablo Carreira)

    ----------------------------------------------------------------------

    Message: 1
    Date: Sun, 21 Mar 2010 13:02:00 -0700
    From: ikechinedu@gmail.com <mailto:ikechinedu@gmail.com>
    Subject: [GRASS-user] ERROR: G_malloc: unable to allocate 2147483648
           bytes at main.c:153
    To: grass-user@lists.osgeo.org <mailto:grass-user@lists.osgeo.org>
    Message-ID:
           <4529578.106556.1269201720004.JavaMail.root@jim.nabble.com
    <mailto:4529578.106556.1269201720004.JavaMail.root@jim.nabble.com>>
    Content-Type: text/plain; charset=us-ascii

    Hi, i am trying extract road network from a raster map but each
    time i run the image filter, i get this error message: ERROR:
    G_malloc: unable to allocate 2147483648 bytes at main.c:153.

    i also connnot use the i.class command on my windows machine which
    is the platform i am working with. please how can i extract a road
    network from raster map on windows platform?
    thank you.
    Nathaniel

    ------------------------------

    Message: 2
    Date: Mon, 22 Mar 2010 00:23:48 +0100
    From: Markus Neteler <neteler@osgeo.org <mailto:neteler@osgeo.org>>
    Subject: Re: [GRASS-user] importing dem files: projection details?
    To: Tyler Smith <tyler.smith@eku.edu <mailto:tyler.smith@eku.edu>>
    Cc: GRASS user list <grass-user@lists.osgeo.org
    <mailto:grass-user@lists.osgeo.org>>
    Message-ID:
           <86782b611003211623x6f777673t62a66fff6526f2d@mail.gmail.com
    <mailto:86782b611003211623x6f777673t62a66fff6526f2d@mail.gmail.com>>
    Content-Type: text/plain; charset=ISO-8859-1

    On Mon, Mar 15, 2010 at 7:38 PM, Tyler Smith <tyler.smith@eku.edu
    <mailto:tyler.smith@eku.edu>> wrote:
    > On 03/15/2010 09:38 AM, Markus Neteler wrote:
    >> On Mon, Mar 15, 2010 at 1:35 PM, Tyler
    Smith<tyler.smith@eku.edu <mailto:tyler.smith@eku.edu>> wrote:
    >>> On 03/15/2010 03:42 AM, Markus Neteler wrote:
    >>>
    >>> Trying the auto route:
    >>>
    >>> grass64 -gui
    >>> select define new location with georeferenced file
    >>> select the dem file: k42.dem
    >>> select the TN transformation, as probably better than the
    default for
    >>> adjacent Kentucky
    >>> enter GRASS with the newly created location and the PERMANENT
    mapset
    >>>
    >>> Results in this error:
    >>>
    >>> "g.proj or projection error: ERROR: default region is invalid
    >>> line 3:<north: 1080:43:46N>"
    >>>
    >>> So GRASS has automatically set up the location using degrees,
    and then
    >>> get
    >>> confused when the raster co-ordinates are provided in meters.
    Which
    >>> appears
    >>> to be fairly close to the sort of problem I ran into when
    setting this up
    >>> manually. What am I missing?
    >>>
    >>
    >> Please post the output of gdalinfo on that file. GRASS uses
    GDAL to detect
    >> projections from metadata.
    >>
    >> Markus
    >>
    >
    > Thanks for help! Here it is:
    >
    > gdalinfo k42.dem
    > Driver: USGSDEM/USGS Optional ASCII DEM (and CDED)
    > Files: k42.dem
    > Size is 1222, 1535
    > Coordinate System is:
    > GEOGCS["NAD83",
    > DATUM["North_American_Datum_1983",
    > SPHEROID["GRS 1980",6378137,298.257222101,
    ...
    > Metadata:
    > AREA_OR_POINT=Point
    > Corner Coordinates:
    >
    > Upper Left ( 1467.054, 1080.729)
    > Lower Left ( 1467.054, 1067.938)
    > Upper Right ( 1477.237, 1080.729)
    > Lower Right ( 1477.237, 1067.938)
    > Center ( 1472.146, 1074.334)
    ...

    I get actually a somewhat different result (GDAL trunk):

    gdalinfo m40.dem
    Driver: USGSDEM/USGS Optional ASCII DEM (and CDED)
    Files: m40.dem
    ...
    Corner Coordinates:
    Upper Left ( 1447.317, 1055.177) (Invalid angle,Invalid angle)
    Lower Left ( 1447.317, 1042.411) (Invalid angle,Invalid angle)
    Upper Right ( 1457.509, 1055.177) (Invalid angle,Invalid angle)
    Lower Right ( 1457.509, 1042.411) (Invalid angle,Invalid angle)
    Center ( 1452.413, 1048.794) (Invalid angle,Invalid angle)
    Band 1 Block=1223x1532 Type=Float32, ColorInterp=Undefined
     NoData Value=-32767
     Unit Type: ft

    You may want to signal this as GDAL bug in the GDAL butracker:
    http://trac.osgeo.org/gdal/

    Unless GDAL doesn't read it correctly, it won't be understood by
    GRASS.
    I tested with
    ftp://ftp.kymartian.ky.gov/dems_usgs/m39.dem.zip

    Markus

    ------------------------------

    Message: 3
    Date: Sun, 21 Mar 2010 22:41:12 -0700 (PDT)
    From: Hamish <hamish_b@yahoo.com <mailto:hamish_b@yahoo.com>>
    Subject: Re: [GRASS-user] ERROR: G_malloc: unable to allocate
           2147483648 bytes at main.c:153
    To: grass-user@lists.osgeo.org
    <mailto:grass-user@lists.osgeo.org>, ikechinedu@gmail.com
    <mailto:ikechinedu@gmail.com>
    Message-ID: <373432.58091.qm@web110015.mail.gq1.yahoo.com
    <mailto:373432.58091.qm@web110015.mail.gq1.yahoo.com>>
    Content-Type: text/plain; charset=us-ascii

    Nathaniel wrote:
    > Hi, i am trying extract road network
    > from a raster map but each time i run the image filter, i
    > get this error message: ERROR: G_malloc: unable to allocate
    > 2147483648 bytes at main.c:153.

    aka it is trying to use >2gig RAM and there is not enough memory.
    Possibly because you are not using a 64bit OS, and possibly because
    you don't actually have that much memory in your computer.
    Maybe try on a smaller dataset?

    > i also connnot use the i.class command on my windows
    > machine which is the platform i am working with.

    you will have to wait for someone to build GRASS 6.4.0RC6 for Cygwin.
    i.class uses UNIX-style Xmonitors which are not available on standard
    MS Windows. (or try GRASS on a Mac or Linux computer/virtual machine)

    Hamish

    ------------------------------

    Message: 4
    Date: Mon, 22 Mar 2010 01:44:01 -0800 (PST)
    From: schorschli <matthiasoswald@hotmail.com
    <mailto:matthiasoswald@hotmail.com>>
    Subject: [GRASS-user] Re: make command (install add on)
    To: grass-user@lists.osgeo.org <mailto:grass-user@lists.osgeo.org>
    Message-ID: <1269251041185-4776893.post@n2.nabble.com
    <mailto:1269251041185-4776893.post@n2.nabble.com>>
    Content-Type: text/plain; charset=us-ascii

    Thanks for answering.

    >Are you sure about this directory?

    >MODULE_TOPDIR should point to the GRASS installation directory which
    >contains bin/, lib/ and other GRASS stuff.

    Yes, the directory is the one containing the grass-folders (bin/,
    lib/ and
    others).

    I could solve this problem. It was not a wrong MODULE_TOPDIR path,
    but wrong
    extensions for the makefiles.

    Now I can run the make command. But this is resulting in hunderts
    of errors
    and warning. Here is a printscreen of the first couple of lignes
    in the
    console...

    http://n2.nabble.com/file/n4776893/errors.png
    http://n2.nabble.com/file/n4776893/errors.png errors.png

    So maybe its better to just give it up with the addons...

    --
    View this message in context:
    http://n2.nabble.com/make-command-install-add-on-tp4764072p4776893.html
    Sent from the Grass - Users mailing list archive at Nabble.com.

    ------------------------------

    Message: 5
    Date: Mon, 22 Mar 2010 17:58:42 +0530
    From: Bishwarup Banerjee <bishwarup.banerjee@gmail.com
    <mailto:bishwarup.banerjee@gmail.com>>
    Subject: [GRASS-user] Helpp needed to call Grass from inside Python
           Plugin
    To: GRASS developers list <grass-dev@lists.osgeo.org
    <mailto:grass-dev@lists.osgeo.org>>,
           grass-user@lists.osgeo.org <mailto:grass-user@lists.osgeo.org>
    Message-ID:
              <78e951a61003220528o10e648a6m2fbd3c878a2897a2@mail.gmail.com
    <mailto:78e951a61003220528o10e648a6m2fbd3c878a2897a2@mail.gmail.com>>
    Content-Type: text/plain; charset="iso-8859-1"

    Hi All,

    I want to call the grass functionalities from inside my python
    plugins, in
    QGIS
    For example: the Grass's raster to polygon script, with out going
    inside the
    grass plugin.
    Can I set the Grass Mapset, and location from inside my python plugin?
    Is this possible?
    my configurations are:
    QGIS 0.11, GRASS 6.3, python 2.5, Windows

    Thank you in advance
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    Message: 6
    Date: Mon, 22 Mar 2010 03:10:42 -0800 (PST)
    From: Gary Nobles <garynobles@yahoo.com <mailto:garynobles@yahoo.com>>
    Subject: [GRASS-user] grass editing
    To: grass-user@lists.osgeo.org <mailto:grass-user@lists.osgeo.org>
    Message-ID: <1269256242668-4777030.post@n2.nabble.com
    <mailto:1269256242668-4777030.post@n2.nabble.com>>
    Content-Type: text/plain; charset=us-ascii

    Hi, I have been editing a grass point dataset in qgis
    unfortunately I have
    just added 400 centroids rather than points! Is there anyway to
    delete just
    the centroids?

    Thanks

    Gary
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    View this message in context:
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    Sent from the Grass - Users mailing list archive at Nabble.com.

    ------------------------------

    Message: 7
    Date: Mon, 22 Mar 2010 13:54:49 +0000
    From: Glynn Clements <glynn@gclements.plus.com
    <mailto:glynn@gclements.plus.com>>
    Subject: Re: [GRASS-user] ERROR: G_malloc: unable to allocate
           2147483648 bytes at main.c:153
    To: Hamish <hamish_b@yahoo.com <mailto:hamish_b@yahoo.com>>
    Cc: grass-user@lists.osgeo.org
    <mailto:grass-user@lists.osgeo.org>, ikechinedu@gmail.com
    <mailto:ikechinedu@gmail.com>
    Message-ID: <19367.30377.130266.683319@cerise.gclements.plus.com
    <mailto:19367.30377.130266.683319@cerise.gclements.plus.com>>
    Content-Type: text/plain; charset=us-ascii

    Hamish wrote:

    > > Hi, i am trying extract road network
    > > from a raster map but each time i run the image filter, i
    > > get this error message: ERROR: G_malloc: unable to allocate
    > > 2147483648 bytes at main.c:153.
    >
    > aka it is trying to use >2gig RAM and there is not enough memory.
    > Possibly because you are not using a 64bit OS, and possibly because
    > you don't actually have that much memory in your computer.
    > Maybe try on a smaller dataset?

    2147483648 is exactly 2GiB; I'm wondering if that's the actual size
    (e.g. 16384 x 16384 x 8bytes/cell) or an uninitialised variable (e.g.
    initialised to INT_MIN in the code and not updated).

    On Linux, it is possible to allocate 2GiB on a 32-bit system, provided
    that there's a contiguous block (in practice, this means that the
    stack size isn't "unlimited"). You don't need that much physical RAM,
    only swap (although performance may be unacceptable if you're relying
    upon swap; it depends upon the access pattern).

    "Desktop" versions of Windows normally only allow 2GiB on 32-bit
    systems. Server versions allow up to 3GiB, and the desktop versions
    can be tweaked to allow it (but it isn't straightforward).

    > > i also connnot use the i.class command on my windows
    > > machine which is the platform i am working with.
    >
    > you will have to wait for someone to build GRASS 6.4.0RC6 for
    Cygwin.
    > i.class uses UNIX-style Xmonitors which are not available on
    standard
    > MS Windows. (or try GRASS on a Mac or Linux computer/virtual
    machine)

    I'll probably be building RC6 for Cygwin some time today.

    --
    Glynn Clements <glynn@gclements.plus.com
    <mailto:glynn@gclements.plus.com>>

    ------------------------------

    Message: 8
    Date: Mon, 22 Mar 2010 12:03:01 -0300
    From: Pablo Carreira <pablotcarreira@hotmail.com
    <mailto:pablotcarreira@hotmail.com>>
    Subject: [GRASS-user] Osgeo4W grass error
    To: <grass-user@lists.osgeo.org <mailto:grass-user@lists.osgeo.org>>
    Message-ID: <SNT114-W54FC77CFFE5D19331A6E4BD6270@phx.gbl>
    Content-Type: text/plain; charset="utf-8"

    Hi, I'am trying to start the latest osgeo4w grass on windows 7 but
    I get an error when I select the dataset. Is it about the
    language? How can I start grass in english and not in portuguese?

    Regards,
    Pablo.

    Here is the error:

    C:\>"C:\OSGeo4W\apps\grass\grass-6.4.0svn"\etc\init.bat -wxpython
    access: Invalid argument
    ERRO:LOCAÃƒâ”œO << C:\teste/<UNKNOWN> >> indisponÃ vel
    Traceback (most recent call last):
     File
    "C:/OSGeo4W/apps/grass/grass-6.4.0svn/etc/wxpython/gis_set.py",
    line 853,
     in <module>
       GRASSStartUp = StartUp(0)
     File
    "C:\OSGeo4W\apps\Python25\lib\site-packages\wx-2.8-msw-unicode\wx\_core.p
    y", line 7935, in __init__
       self._BootstrapApp()
     File
    "C:\OSGeo4W\apps\Python25\lib\site-packages\wx-2.8-msw-unicode\wx\_core.p
    y", line 7509, in _BootstrapApp
       return _core_.PyApp__BootstrapApp(*args, **kwargs)
     File
    "C:/OSGeo4W/apps/grass/grass-6.4.0svn/etc/wxpython/gis_set.py",
    line 824,
     in OnInit
       StartUp = GRASSStartup()
     File
    "C:/OSGeo4W/apps/grass/grass-6.4.0svn/etc/wxpython/gis_set.py",
    line 165,
     in __init__
       self._set_properties()
     File
    "C:/OSGeo4W/apps/grass/grass-6.4.0svn/etc/wxpython/gis_set.py",
    line 206,
     in _set_properties
       self.OnSetDatabase(None)
     File
    "C:/OSGeo4W/apps/grass/grass-6.4.0svn/etc/wxpython/gis_set.py",
    line 664,
     in OnSetDatabase
       self.OnSelectLocation(None)
     File
    "C:/OSGeo4W/apps/grass/grass-6.4.0svn/etc/wxpython/gis_set.py",
    line 616,
     in OnSelectLocation
       self.listOfLocations[self.lblocations.GetSelection()]))
     File
    "C:/OSGeo4W/apps/grass/grass-6.4.0svn/etc/wxpython/gis_set.py",
    line 584,
     in UpdateMapsets
       stderr=None)
     File
    "C:\OSGeo4W\apps\grass\grass-6.4.0svn\etc\wxpython\gui_modules\gcmd.py",
    line 356, in __init__
       _("Error: ") + self.GetError()))
     File
    "C:\OSGeo4W\apps\grass\grass-6.4.0svn\etc\wxpython\gui_modules\gcmd.py",
    line 449, in GetError
       return unicode(msg, "utf-8")
    UnicodeDecodeError: 'utf8' codec can't decode bytes in position
    4-5: invalid dat
    a

    _________________________________________________________________
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    instalar gratuitamente.
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Micha Silver
Arava Development Co. +972-52-3665918
http://www.surfaces.co.il

Micha_Silver · April 1, 2010, 5:55am

Thanks Micha,
I ran r.thin and got just one line. is there a way i can improve it?

Good, so we’re making progress…
How many polygon areas did you create in the training map? Does it cover various portions of the roads?

···

-- 
Micha Silver
[http://www.surfaces.co.il/](http://www.surfaces.co.il/)
Arava Development Co.  +972-52-3665918

Micha_Silver · April 1, 2010, 12:23pm

i created 11 polygons from different portions of the road.

So if I understand correctly, the procedure is working, but you’re not getting the results you’d expect?
Maybe you could supply to the grass-users list some URL’s of images of what the satellite rasters look like, with your training polygons, and the resulting roads. Then perhaps someone will be able to suggest how to get more complete results.

···

-- 
Micha Silver
[http://www.surfaces.co.il/](http://www.surfaces.co.il/)
Arava Development Co.  +972-52-3665918

Micha_Silver · April 2, 2010, 12:27pm

Nathaniel Iwuchukwu wrote:

here are the image results of my works. am trying to upload it on my page

If you do upload the images, post also to the list.

It looks like all the areas that are *not* roads are also being classified. Everywhere that appears purple in you classification image needs to be set to null. You do this with:
r.null <classified_raster> setnull=<the value which displays purple>

You want to be left with a raster with values *only* where there are roads. Everything else should be null. Then go ahead and run:
r.thin and r.to.vect <classified_raster_thin> feature=line out=roads

Cheers,
Micha

2010/4/1 Micha Silver <micha@arava.co.il <mailto:micha@arava.co.il>>

    On 04/01/2010 02:52 PM, Nathaniel Iwuchukwu wrote:

    i created 11 polygons from different portions of the road.

    So if I understand correctly, the procedure is working, but you're
    not getting the results you'd expect?

    Maybe you could supply to the grass-users list some URL's of
    images of what the satellite rasters look like, with your training
    polygons, and the resulting roads. Then perhaps someone will be
    able to suggest how to get more complete results.

Micha_Silver · April 2, 2010, 3:01pm

Nathaniel Iwuchukwu wrote:

I figured it out.
here are my new output. though the lines are scattered. can it be improved?

Again, Nathaniel, keep the discussion on the list, both to get more responses, and for future generations.
The next step you might try is using the v.clean command on this vector to remove very small lines. It has a tool, rmdangle to get rid of all the small X's around the actual roads. You will have to experiment with the "thresh" parameter to get it right.

Regards,
Micha

On Fri, Apr 2, 2010 at 5:41 AM, Nathaniel Iwuchukwu <ikechinedu@gmail.com <mailto:ikechinedu@gmail.com>> wrote:

    Thanks Micha,
    I was thinking of running the r.mapcalc command but not sure of
    the exact argument to use.
    is there a command i can run to show me the values of the colors
    on the map?
    Thanks
    Nathaniel

    On Fri, Apr 2, 2010 at 8:27 AM, Micha Silver <micha@arava.co.il
    <mailto:micha@arava.co.il>> wrote:

        Nathaniel Iwuchukwu wrote:

            here are the image results of my works. am trying to
            upload it on my page

        If you do upload the images, post also to the list.

        It looks like all the areas that are *not* roads are also
        being classified. Everywhere that appears purple in you
        classification image needs to be set to null. You do this with:
        r.null <classified_raster> setnull=<the value which displays
        purple>

        You want to be left with a raster with values *only* where
        there are roads. Everything else should be null. Then go ahead
        and run:
        r.thin and r.to.vect <classified_raster_thin> feature=line
        out=roads

        Cheers,
        Micha

            2010/4/1 Micha Silver <micha@arava.co.il
            <mailto:micha@arava.co.il> <mailto:micha@arava.co.il
            <mailto:micha@arava.co.il>>>

               On 04/01/2010 02:52 PM, Nathaniel Iwuchukwu wrote:

                   i created 11 polygons from different portions of
                the road.

               So if I understand correctly, the procedure is working,
            but you're
               not getting the results you'd expect?

               Maybe you could supply to the grass-users list some
            URL's of
               images of what the satellite rasters look like, with
            your training
               polygons, and the resulting roads. Then perhaps someone
            will be
               able to suggest how to get more complete results.

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Micha Silver
Arava Development Co. +972-52-3665918
http://www.surfaces.co.il