Standalone Python/PyQGIS path setup

Question

I'm trying to run a script using python. The script requires some qgis functionality. I believe I have set the path, pythonpath, etc. correctly. The OS is Windows 7 64-bit with qgis located at the non-standard location Z:\Program Files\QGIS 2.18.

I receive

"Z:\Program Files\QGIS 2.18\bin\python.exe" "Z:/Locating Incident  
Response/Solver/pyspatialopt-master/pyspatialopt-master/examples
/binary_mclp_qgis.py"

Traceback (most recent call last):
File "Z:/Locating Incident Response/Solver/pyspatialopt-master
/pyspatialopt-master/examples/binary_mclp_qgis.py", line 11, in <module>
import qgis
File "Z:\Program Files\QGIS 2.18\apps\qgis\python\qgis\__init__.py", line 
27, in <module>
from qgis.core import QgsFeature, QgsGeometry
File "Z:\Program Files\QGIS 2.18\apps\qgis\python\qgis\core\__init__.py",
line 30, in <module>
from qgis._core import *
ImportError: DLL load failed: The specified module could not be found.

Process finished with exit code 1

What am I doing wrong?

(I should note that the loading of qgis works fine in the Python console. Not surprisingly!)

Answer 1

I think the best way to do this is to use the OSGeo4W shell.

I still need to set a couple of environment variables

set PYTHONPATH=Z:\Program Files\QGIS 2.18\apps\qgis\python
set PATH=Z:\Program Files\QGIS 2.18\apps\qgis\bin;%PATH%

but at least I can import qgis!