I try running the v.clean tool using QGIS 3.4. As input I use a vector line layer (I checked the validity and everything is fine), but running the algorithm I get the following error:

Traceback (most recent call last):
File "D:/Programme/OSGeo4W/apps/qgis/./python/plugins\processing\algs\grass7\Grass7Algorithm.py", line 415, in processAlgorithm
Grass7Utils.executeGrass(self.commands, feedback, self.outputCommands)
File "D:/Programme/OSGeo4W/apps/qgis/./python/plugins\processing\algs\grass7\Grass7Utils.py", line 372, in executeGrass
for line in iter(proc.stdout.readline, ''):
File "D:\Programme\OSGeo4W\apps\Python37\lib\codecs.py", line 322, in decode
(result, consumed) = self._buffer_decode(data, self.errors, final)
UnicodeDecodeError: 'utf-8' codec can't decode byte 0xf6 in position 81: invalid start byte

Execution failed after 0.50 seconds

Since it is says it is a decoding error I checked the encoding and it is encoded in UTF-8.

Does anybody know how to solve the error?

  • You are probably using some special "Buchstaben". Try to play around with encoding of your vector line layer (e.g. using ISO 8859-1, ISO 8859-15, Windows 1250). However, the UTF-8 should work fine. Moreover, I would like you to describe a way how the original vector line layer was achieved? I assume that the issue is about the original vector line layer encoding. – Taras Nov 13 '18 at 13:06
  • I tried different layers from different sources now (even a new line layer I just created) and on use with v.clean I get the exact same error on every layer. I also tried different encodings for the layers and no matter which encoding I use, I get the same error. So I assume the problem does not come from the layers, but from QGIS itself. – gHupf Nov 13 '18 at 15:07
  • I tried by myself and also almost the same error UnicodeDecodeError: 'charmap' codec can't decode byte 0x81 in position 2: character maps to Execution failed after 0.30 seconds – Taras Nov 13 '18 at 15:21
  • 1
    I tried in QGIS 2.18 and everything works fine. So it seems to be an error of 3.4. I don't know about other 3.x versions. – gHupf Nov 13 '18 at 16:50

QGIS version 3.4.2:

The bug is fixed in version 3.4.2 and everything works without error messages.

Note: This only works since QGIS version 3.4.2, if you use a previous version of 3.x please update QGIS or check a possible workaround I mentioned below.

Below 3.4.2:

In versions 3.x the error is a known QGIS bug and is triggered by regional language settings on Windows.

A current workaround is to switch the Windows system language to English (US) and the error will disappear.

| improve this answer | |
  • Sorry for retroposting. I have QGIS Noosa 3.6.1 and problem still remains. I switched regional language to English (US) and, in my case, LASTools still doesn't work. – Sergey N Jul 16 '19 at 6:37

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