Import Qgis.core in Spyder

Question

I'm currently trying to translate the tasks I performed using Qgis (3.16.5) into a Python (Spyder) script, such that I will be able to perform these tasks on multiple files more easily.

However, I'm experiencing difficulties importing Qgis into Spyder. First, I received an error. After looking on internet, I found many topics related to this and I tried most of them.

Most of them were related to changing the PYTHONPATH and PATHs. I ended up with the script below: '''

@echo off
  SET OSGEO4W_ROOT=C:\OSGeo4W64
  call "%OSGEO4W_ROOT%"\bin\o4w_env.bat
  call "%OSGEO4W_ROOT%"\apps\grass\grass78\etc\env.bat
  @echo off
  path %PATH%;%OSGEO4W_ROOT%\apps\qgis\bin
  path %PATH%;%OSGEO4W_ROOT%\apps\grass\grass78\lib

  set PYTHONPATH=%PYTHONPATH%;%OSGEO4W_ROOT%\apps\qgis\python;
  set PYTHONPATH=%PYTHONPATH%;%OSGEO4W_ROOT%\apps\Python27\Lib\site-packages
  cmd.exe

However, I now get a new error: "DLL load failed while importing _core: Cannot find procedure" and still cannot import qgis.core. I tried this code both with OSGeo4W64 and with a Qgis version downloaded without OSGeo4W64.

How can I import the Qgis.core?

Answer 1

I'm somewhat confused that you have a recent QGIS (3.16.5), but that you're starting a Python 2.7? QGIS 3 uses Python 3, not 2.7 and it won't work.

At any rate, in your QGIS installation, you'll find some batch files, in my case it's this one c:\Program Files\QGIS 3.18\bin\py3_env.bat and python-qgis.bat.

So open your command line, and run:

cd c:\Program Files\QGIS 3.18\bin
CALL py3_env.bat
CALL python-qgis.bat

This'll start the QGIS interpreter, I can succesfully import qgis.core here.

c:\Program Files\QGIS 3.18\bin>python
Python 3.7.0 (v3.7.0:1bf9cc5093, Jun 27 2018, 04:59:51) [MSC v.1914 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import qgis.core
>>> exit()

You can check whether it's starting the right python now by e.g. running:

where python

This should return the QGIS python as its first entry:

c:\Program Files\QGIS 3.18\apps\Python3.7\python.exe

Now, you could try starting Spyder (just run spyder in the command line). However, it has to be installed for this QGIS Python interpreter speficically. I think the default QGIS installation by default comes with pip, if you install via OSGeo4W, see: Do not have pip for my QGIS Python.

Note, however, that this is somewhat hap-hazard: QGIS and Spyder have a shared dependency in (Py)Qt and they might e.g. demand different versions.

If you run into trouble, you could try using a (non-Qt) editor/IDE like Visual Studio Code (again, probably start it after setting all the environmental variables right with the batch files mentioned above), or possibly something from jupyter.