[GIS] Where exactly are qgis.gui and qgis.core located

pyqgispython

I'm trying to create a standalone QGIS app using PyQGIS. I'll be deploying it by copying the install folder of QGIS and source folder of my app, and so for the testing purposes I copied QGIS install folder (1.8.0) to some other computer without QGIS installation to begin with; then I tried to test the qgis.gui and qgis.core imports, but no matter what PYTHONPATH (or PATH) I set, I keep getting ImportError "no module named …".

What's weird is, if I modify qgis.bat to this new location and run it, QGIS opens without a problem and all imports work through console inside QGIS. Then I simply duplicated qgis.bat and removed the last line which runs QGIS then added the line which runs my application instead. For some reason, imports are still unavailable, so I'm wondering where are actual Python binding files for qgis_gui.dll and qgis_core.dll because I can't find them anywhere inside QGIS install directory.

My .bat looks like this:

@echo off
SET OSGEO4W_ROOT=c:\IMS\Qgis
call "%OSGEO4W_ROOT%"\bin\o4w_env.bat
call "%OSGEO4W_ROOT%"\apps\grass\grass-6.4.2\etc\env.bat
@echo on
PATH %PATH%;%OSGEO4W_ROOT%\apps\qgis\bin;%OSGEO4W_ROOT%\apps\grass\grass-6.4.2\lib;%OSGEO4W_ROOT%\apps\qgis\python\qgis;
SET PYTHONPATH = c:\IMS\QGis\apps\qgis\bin\
python c:\IMS\IMS\ims.py

Best Answer

This is the correct path setup:

@echo off
SET OSGEO4W_ROOT=c:\IMS\Qgis
call "%OSGEO4W_ROOT%"\bin\o4w_env.bat
call "%OSGEO4W_ROOT%"\apps\grass\grass-6.4.2\etc\env.bat

set PYTHONPATH=C:\OSGeo4W\apps\qgis\python
Set PATH=C:\OSGeo4W\apps\qgis\bin;%PATH%
set QGISHOME=C:\OSGeo4W\apps\qgis\

qgis.core and qgis.gui are located in the qgis\python\qgis folder but you only set PYTHONPATH to the qgis\python folder because qgis is a package.

PYTHONPATH

The PYTHONPATH is set for the cmd you launch. This means that you have to set it globally on your system

Go to Control Panel -> System-> Advanced.

Click on the 'Environment Variables' button.

In the 'System Variables' panel that appears, click New and enter PYTHONPATH in the 'Variable Name' field. In the 'Variable Value' field enter the path to QGIS.

Or you can set it directly on the cmd command line just before launching the python interpreter with :

set PYTHONPATH=%PYTHONPATH%;C:\My_python_lib

PATH

The DLL which will be used by the qgis python module must be in your path. Just as you set the PYTHONPATH above, set the PATH environment variable so that it contains the directory where qgis_core.dll is located.

The directory to add is probably D:\Program Files (x86)\Quantum GIS Wroclaw\apps\qgis But check that qgis_core.dll is really there.

OSGEO4W

As was suggested in another answer, OSGEO4W install and sets everything up for you. It will install another Python though, which can complicate things when you want to install third party Python modules not available in OSGEO4W.

You would as well get the latest QGIS version too, which is 1.7.4 (1.8 coming soon).

[GIS] Running Python outside of QGIS – (ImportError: No module named qgis.core)

This solution worked for me in Windows 7x64 SP1 with Python 2.7.13-64bit and QGIS 2.14.9x64 standalone install (important: Python and QGIS architectures must match). This solution involves virtualenv (install instructions) which means you won't need to play with Python environment variables which can be tricky if you're doing other Python development with different versions of Python.

Editing Path

Edit the PATH variable by going to Control Panel>System>Advanced system settings then click on Environment Variables in the below window.

Edit the PATH User Variable and add ;C:\Program Files\QGIS Essen\bin\;C:\Program Files\QGIS Essen\apps\qgis-ltr\bin, note the version Essen as well as the use of qgis-ltr\bin here. The latter was necessary in order for Python to be able to find the qgis_core.dll.

Create a Virtual Environment

Create a new virtual environment in the command line: virtualenv qgisenv -p "C:\path\to\Python27.exe" specifying the Python 2.7 location. Note this will create a folder for your virtual environment, you should put any projects you develop in here.

Next add paths to the installed QGIS python libraries to the virtual environment's site-packages folder using .pth files. For example in QGIS 2.14.9 python packages can be found at the following locations (why?), so create a file qgisenv\Lib\site-packages\qgis.pth with:

C:\Program Files\QGIS Essen\apps\qgis-ltr\python
C:\Program Files\QGIS Essen\apps\Python27\
C:\Program Files\QGIS Essen\apps\Python27\Lib\
C:\Program Files\QGIS Essen\apps\Python27\Lib\site-packages
C:\Program Files\QGIS Essen\bin
C:\Program Files\QGIS Essen\include
C:\Program Files\QGIS Essen\apps\qgis-ltr\bin

this list can probably be shortened

Activate Environment and Test

Back in the Command Prompt cd into the qgisenv directory and activate the virtual environment with Scripts\activate

Then open a python console and type

>>> from qgis.core import *

And you should be good to go!

How to use an IDE?

If you use anaconda and Spyder, you could use conda to set up the environment and then call spyder after activating the environment. Other IDEs might have the option of setting a virtual environment from the settings.