[GRASS-user] Using pipes in python scripts

GRASS GRASS user
1

I'm making progress translating my shell script to Python but ran into another stumbling block. I would like to convert the following shell script command to the python scrip:
--
v.out.ascii $randomName fs=' ' | r.what input=$resampName> $pointTableName
--

I tried various combinations of grass.pipe_command and grass.feed_command but haven't been able to get it to work.

Any help would be appreciated.

Ned

2

Ned Horning wrote:

I'm making progress translating my shell script to Python but ran into
another stumbling block. I would like to convert the following shell
script command to the python scrip:
--
v.out.ascii $randomName fs=' ' | r.what input=$resampName> $pointTableName
--

I tried various combinations of grass.pipe_command and
grass.feed_command but haven't been able to get it to work.

Using pipe_command() and feed_command() will give you two pipes (one
each), but you only want one. Use start_command():

  outf = file(pointTableName, 'w')
  p1 = grass.pipe_command('v.out.ascii',
    input = randomName,
    fs = ' ')
  p2 = grass.start_command('r.what',
    input = resampName,
    stdin = p1.stdout,
    stdout = outf)
  outf.close()
  p1.stdout.close()
  p1.wait()
  p2.wait()

start_command() is the most general function; all of the others
(except exec_command()) end up invoking start_command().

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

3

Hello,

since some weeks I have the libgdal-package in my Ubuntu (Karmic) update manager, listed under ‘distribution update’ (Distributionsaktualisierung) but I can’t update it.

Now I tried to install this package from lauchpad.net: libgdal1-1.6.0-grass_1.6.2-3_amd64.deb

The result is this absent dependency expression: “Fehler: Abhängigkeit kann nicht erfüllt werden: grass640-5+39438” The GRASS version I’ve installed is 6.4.0RC6. Asks the expression […]grass640-5[…] for version RC5?

Regards and thanks for a clue,
Benedikt

4

On Mon, Jul 5, 2010 at 9:39 AM, Benedikt Ziegler
<benedikt.ziegler@gmx.de> wrote:

Hello,

since some weeks I have the libgdal-package in my Ubuntu (Karmic) update
manager, listed under 'distribution update' (Distributionsaktualisierung)
but I can't update it.

Now I tried to install this package from lauchpad.net:
libgdal1-1.6.0-grass_1.6.2-3_amd64.deb

The result is this absent dependency expression: "Fehler: Abhängigkeit kann
nicht erfüllt werden: grass640-5+39438" The GRASS version I've installed is
6.4.0RC6. Asks the expression [...]grass640-5[...] for version RC5?

Looks like that - perhaps it should have been written as >= grass640-5+39438?

I think that you need to open a bug report in launchpad.

Markus

5

Am 05.07.2010 20:21, schrieb Markus Neteler:

On Mon, Jul 5, 2010 at 9:39 AM, Benedikt Ziegler
<benedikt.ziegler@gmx.de> wrote:
   

Hello,

since some weeks I have the libgdal-package in my Ubuntu (Karmic) update
manager, listed under 'distribution update' (Distributionsaktualisierung)
but I can't update it.

Now I tried to install this package from lauchpad.net:
libgdal1-1.6.0-grass_1.6.2-3_amd64.deb

The result is this absent dependency expression: "Fehler: Abhängigkeit kann
nicht erfüllt werden: grass640-5+39438" The GRASS version I've installed is
6.4.0RC6. Asks the expression [...]grass640-5[...] for version RC5?
     

Looks like that - perhaps it should have been written as>= grass640-5+39438?

I think that you need to open a bug report in launchpad.

Markus

A view in Synaptic package manager shows that there is libgdal1-1.6.0-grass AND libgdal1-1.7.0-grass installed on my system. Is the older version obsolete and can completely uninstalled instead of updating?

Benedikt