[GIS] “ImportError: no module named qgis.core” in standalone app

installationpyqgis

I am developing a standalone app (in Windows) using libraries from QGIS. When I run the script in cmd, I get the ImportError: no module named qgis.core. I read in several posts that I need to configure the PYTHONPATH and PATH but I also read that with OSGEO4W installation there is no need to configure.

How do I do that?

I am very confused and I try several ways but without success. Now I am reinstalling QGIS thorugh OSGEO4W.

So, I need to import QGIS libraries in a script outside QGIS. This script runs inside Python27 folder that I have already installed for other app.

Is it possible to use the QGIS libraries through this directory?

If not what is the solution?

I resolved the import qgis.core error, just following the instructions of how to import qgis modules outside qgis. Now the error is different: ImportError: DLL load failed: %1 is not a valid Win32 application. And the error is related with import sip. I search and find that I use python from OSGEO4W (64bits) and external python (32 bits).

How I can solve it?

Best Answer

I'm not sure if it helps for you but in principle you set paths either by writing the commands into the DOS-box (started with cmd) or by setting them via a batch file. To use eclipse with QGIS the following lines have been recommended. All you have to do is to write them into a plain text file and give its filename a .bat ending.

Just make sure to replace by your own file names. Instead of eclipse.exe (last line) use your standalone app:

call "C:\Program Files (x86)\QGIS Wien\bin\o4w_env.bat"  
set PATH=%PATH%;C:\Program Files (x86)\QGIS Wien\apps\qgis\bin;C:\Program Files (x86)\QGIS Wien\bin  
SET PYTHONHOME=C:\Program Files (x86)\QGIS Wien\apps\Python27  
Set PYTHONPATH=C:\Program Files (x86)\QGIS Wien\apps\qgis\python  
eclipse.exe

Related Solutions

QGIS OSGeo4W – Import Error for qgis.core in Shell Script

Finally found the proper way of running processing algorithms in PyQGIS standalone scripts.

This answer is based on answers to Problem with import qgis.core when writing a stand-alone PyQGIS script and to Error: Algorithm not found, which is in turn based on a Qgis-dev mailing-list discussion.

I suggest you to follow the work flow given in Problem with import qgis.core when writing a stand-alone PyQGIS script to enable your QGIS libraries in your OSGeo4W Shell. Once you have your QGIS libraries working properly, we can proceed to the 2nd part of your question: running processing algorithms in a standalone PyQGIS script.

I've modified your original script a bit and tested it on Windows 7 and GNU/Linux. I use processing version 2.2.0-2 and suggest you to use this version, which is the current one at the moment of writing the answer.

import os, sys, glob

# Prepare the environment
from qgis.core import * # qgis.core must be imported before PyQt4.QtGui!!!
from PyQt4.QtGui import *
app = QApplication([])
QgsApplication.setPrefixPath("C:\\Program Files\\QGIS Brighton\\apps\\qgis", True) # The True value is important
QgsApplication.initQgis()

from os.path import expanduser
home = expanduser("~")

#   Folder path of the Results for shapefiles
path_dir = home + "\Desktop\Test\\"
path_res = path_dir + "Results\\"

# Prepare processing framework 
sys.path.append( home + '\.qgis2\python\plugins' )
from processing.core.Processing import Processing
Processing.initialize()
from processing.tools import *

def run():
    outputs_1=general.runalg("qgis:creategrid", 1000, 1000, 24108, 18351.157175, 258293.802316, 665638.226408, 1, 'EPSG:7405',  None)
    #   Set directory, search for all polygon .shp files and run the Create Grid and Clip algorithms then output results into Results folder
    os.chdir(path_dir + "Shapefiles\\")
    for fname in glob.glob("*.shp"):        
        outputs_2=general.runalg("qgis:clip", outputs_1['SAVENAME'], fname, path_res  + "/"+ fname)

run()

QgsApplication.exitQgis()
#   Remove the above line when running in QGIS

Note that I have taken the grid creation out of the for loop, as you don't really need a new grid to perform each clip.

This should do the trick!

[GIS] ImportError: no module named site

Try this:

SET OSGEO4W_ROOT=C:\OSGeo4W
SET QGISNAME=qgis
SET QGIS=%OSGEO4W_ROOT%\apps\%QGISNAME%
set QGIS_PREFIX_PATH=%QGIS%

CALL %OSGEO4W_ROOT%\bin\o4w_env.bat

: Python Setup
set PATH=%OSGEO4W_ROOT%\bin;%QGIS%\bin;%PATH%
SET PYTHONHOME=%OSGEO4W_ROOT%\apps\Python27
set PYTHONPATH=%QGIS%\python

Related Question