Using Python script to control GRASS GIS from outside?

Question

I am working with GRASS 6.4.3 and python 2.7.6 under WIN 8.1.

I am a novice with computer science and coding, and I have seen many posts including those:

• Is it possible to use GRASS GIS in Python stand alone scripts?
• GRASS and Python, in order to control GRASS from outside by using python.

Here's my python code, which wants to use the GRASS module g.list to list my raster data in GRASS. I type those code in Python IDLE.

import os
import sys

gisbase = os.environ['GISBASE'] = 'C:\OSGeo4W64\apps\grass\grass-6.4.3'  #GISBASE needs to point the root of the GRASS installation directory
gisrc = 'C:\Users\Heinz\Documents\grassdata'
gisdbase = 'C:\Users\Heinz\Documents\grassdata'
location = 'newLocation'
mapset = 'TC'
LD_LIBRARY_PATH = 'C:\OSGeo4W64\apps\grass\grass-6.4.3\lib'
PATH = 'C:\OSGeo4W64\apps\grass\grass-6.4.3\etc';'C:\OSGeo4W64\apps\grass\grass-6.4.3\etc\python';'C:\OSGeo4W64\apps\grass\grass-6.4.3\lib';'C:\OSGeo4W64\apps\grass\grass-6.4.3\bin';'C:\Python27';'C:\OSGeo4W64\apps\Python27';'C:\OSGeo4W64\apps\msys'
PYTHONLIB = 'C:\Python27'
PYTHONPATH = 'C:\OSGeo4W64\apps\grass\grass-6.4.3\etc\python'
GRASS_SH = 'C:\OSGeo4W64\apps\msys\bin\sh.exe'


sys.path.append(os.path.join(os.environ['GISBASE'], 'etc', 'python'))

import grass.script as grass

And I have set every path in my code as environment variable in the windows control panel.

As I run module, I got the error:

Which line of my code is wrong or not necessary and what code should I add to my python script, or can't I use Python IDLE to do this?

---

@ustroetz I have found no file in my computer named .grassrc6 , so I create a new file named .grassrc6(which is empty), adding a line in my code:

gisrc = 'C:\Users\Heinz\.grassrc6'

But still got the same error.

Did I misunderstand the instruction in the post？

---

I create a text file named grass.pth in this folder C:\OSGeo4W\apps\python27\lib\site-packages, and type those two lines in it:

Here is the list of my environment variables I have set in windows penal:

GISBASE = C:\OSGeo4W64\apps\grass\grass-6.4.3
GISRC = C:\Users\Heinz\Documents\grassdata
Path = 
C:\Python27
C:\OSGeo4W64\apps\grass\grass-6.4.3
C:\Users\Heinz\Documents\grassdata
C:\OSGeo4W64\apps\grass\grass-6.4.3\lib
C:\OSGeo4W64\apps\grass\grass-6.4.3\etc\python
C:\OSGeo4W64\apps\grass\grass-6.4.3\etc
C:\OSGeo4W64\apps\grass\grass-6.4.3\bin
C:\OSGeo4W64\apps\Python27
C:\OSGeo4W64\apps\msys
C:\OSGeo4W64\apps\grass\grass-6.4.3\scripts
C:\OSGeo4W64\bin
C:\OSGeo4W64\apps\Python27\Lib\site-packages

then I ran my python script, and got the same error:

You can see that I have added this line:sys.path.append('C:\OSGeo4W\bin') in my script(it's because the script didn't work before I added it), but it still got the same error.

---

@Martin, I have found that I have three places where python installed:

C:\OSGeo4W64\apps\Python27
C:\Python27
C:\Program Files (x86)\Quantum GIS Lisboa\apps\Python27

and I also found site-packages files in those places, so I copied grass.pth to those places, but my script still can't work.

I also found this python-related file:

C:\Users\Heinz\Downloads\http%3a%2f%2fdownload.osgeo.org%2fosgeo4w%2f\x86_64\release\python

I don't know if this keeps my script useless, should I delete this file, or it doesn't matter?

I have tried this in cmd:

I will keep trying to make my script work!

Answer 1

After some hard work, I got my GRASS working with Python using a .pth file in the sitepackages folder.

To try this, do to the following steps:

1. Go to the folder C:\OSGeo4W\apps\python27\lib\site-packages
2. Create a file called grass.pth and open it with an editor

3. Enter the following two lines (assuming your GRASS was installed with OSGeo4W; check the paths to be sure):

   C:\OSGeo4W\apps\grass\grass-6.4.3\etc\python C:\OSGeo4W\bin

4. Save and close the file

5. Try the following statement in your Python Script

   import grass.script as grass

P.S.: To make that work, you have to set your enviroment variables as described in posts above.

Another option might be to add the C:\OSGeo4W\bin path to your script with sys.path.append as you did with other paths

Once it works, check out the following post for getting to run the grass tools: GRASS Geoprocessing in Python Script

Answer 2

You have not connected Grass GIS and Python probably. So there is nothing particular wrong with your code, but Python cannot import the grass.script module.

Probably you didn't set the environment variables yet. You can find good documentation on how to setup Grass GIS in order to use it in Python on the OSGEO Grass Wiki Site.

Answer 3

import sys
import os

gisbase = os.environ['GISBASE'] = 'C:\OSGeo4W64\apps\grass\grass-6.4.3'  #GISBASE needs to point the root of the GRASS installation directory
gisdbase = 'C:\Users\Heinz\Documents\grassdata'
LD_LIBRARY_PATH = 'C:\OSGeo4W64\apps\grass\grass-6.4.3\lib'
PATH = 'C:\OSGeo4W64\apps\grass\grass-6.4.3\etc';'C:\OSGeo4W64\apps\grass\grass-6.4.3\etc\python';'C:\OSGeo4W64\apps\grass\grass-6.4.3\lib';'C:\OSGeo4W64\apps\grass\grass-6.4.3\bin';'C:\Python27'
PYTHONLIB = 'C:\Python27'
PYTHONPATH = 'C:\OSGeo4W64\apps\grass\grass-6.4.3\etc\python'

sys.path.append(os.path.join(os.environ['GISBASE'], 'etc', 'python'))

import grass.scripts