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I'm new to QGIS, and have never used the Python console. I have created a complex layer in QGis using an experimental, plugin which I had to manually install. It contains 91506 features; lines going around the country. I'm trying to run Q-chainage plugin to put points along these lines at regular intervals. I get the following error:

An error has occurred while executing Python code: 
AttributeError: 'NoneType' object has no attribute 'asPoint' 
Traceback (most recent call last):
  File "C:/Users/j6525/.qgis2/python/plugins\qchainage\qchainagedialog.py", line 124, in accept
    decimal)
  File "C:/Users/j6525/.qgis2/python/plugins\qchainage\chainagetool.py", line 199, in points_along_line
    divide)
  File "C:/Users/j6525/.qgis2/python/plugins\qchainage\chainagetool.py", line 69, in create_points_at
    point = QgsGeometry.fromPoint(point.asPoint())
AttributeError: 'NoneType' object has no attribute 'asPoint'

Python version: 2.7.5 (default, May 15 2013, 22:44:16) [MSC v.1500 64 bit (AMD64)] 
QGIS version: 2.18.14 Las Palmas, ff83b9a479 
Python Path:
•   C:/PROGRA~1/QGIS2~1.18/apps/qgis/./python/plugins\processing
•   C:/PROGRA~1/QGIS2~1.18/apps/qgis/./python
•   C:/Users/j6525/.qgis2/python
•   C:/Users/j6525/.qgis2/python/plugins
•   C:/PROGRA~1/QGIS2~1.18/apps/qgis/./python/plugins
•   C:\PROGRA~1\QGIS2~1.18\bin\python27.zip
•   C:\PROGRA~1\QGIS2~1.18\apps\Python27\DLLs
•   C:\PROGRA~1\QGIS2~1.18\apps\Python27\lib
•   C:\PROGRA~1\QGIS2~1.18\apps\Python27\lib\plat-win
•   C:\PROGRA~1\QGIS2~1.18\apps\Python27\lib\lib-tk
•   C:\PROGRA~1\QGIS2~1.18\bin
•   C:\PROGRA~1\QGIS2~1.18\apps\Python27
•   C:\PROGRA~1\QGIS2~1.18\apps\Python27\lib\site-packages
•   C:\PROGRA~1\QGIS2~1.18\apps\Python27\lib\site-packages\jinja2-2.7.2-py2.7.egg
•   C:\PROGRA~1\QGIS2~1.18\apps\Python27\lib\site-packages\markupsafe-0.23-py2.7-win-amd64.egg
•   C:\PROGRA~1\QGIS2~1.18\apps\Python27\lib\site-packages\win32
•   C:\PROGRA~1\QGIS2~1.18\apps\Python27\lib\site-packages\win32\lib
•   C:\PROGRA~1\QGIS2~1.18\apps\Python27\lib\site-packages\Pythonwin
•   C:\PROGRA~1\QGIS2~1.18\apps\Python27\lib\site-packages\Shapely-1.2.18-py2.7-win-amd64.egg
•   C:\PROGRA~1\QGIS2~1.18\apps\Python27\lib\site-packages\wx-2.8-msw-unicode
•   C:\PROGRA~1\QGIS2~1.18\apps\Python27\lib\site-packages\xlrd-0.9.2-py2.7.egg
•   C:\PROGRA~1\QGIS2~1.18\apps\Python27\lib\site-packages\xlwt-0.7.5-py2.7.egg
•   C:/Users/j6525/.qgis2//python
C:/Users/j6525/Desktop/GIS assessment/02_fields_of_conflict/02_fields_of_conflict
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6
  • Does the plugin work for s simple dataset with a handful of features? – user30184 Dec 2 '17 at 20:52
  • Yes it does. This situation may be arising from Qchainage being applied to more than one island boundary. (Sea may be a null value). – SchoolBoy Dec 2 '17 at 21:41
  • 'NoneType' Error means that 'point' is of type 'None', so something before that line went wrong. I doubt we can help you here without knowing the code of the functions "points_along_line" and "create_points_at". And I think contacting the developer would be more helpful. – pLumo Dec 4 '17 at 8:41
  • You could try to avoid problematic geometries with adding if point is None: return None after point = geom.interpolate(startpoint) (of course properly aligned...) in C:/Users/j6525/.qgis2/python/plugins\qchainage\chainagetool.py Line 66. But I don't know if that produces some errors later on. – pLumo Dec 4 '17 at 8:52
  • This problem has been solved. – SchoolBoy Dec 6 '17 at 19:53
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This problem has been solved.

the issue is that some lines are too short to create a point (because 2 points of the analysis were too close). This is a workaround: - Go to Vector -> Geometry Tools -> Check Validity - Select as input layer the one with the lcps and click Run (it can take a while for the battlefields) - Use the QChainage plugin on the "Valid output" new layer created by the previous step.

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