PyQGIS – Processing.runalg() Throws ‘TypeError: Catching Classes That Do Not Inherit from BaseException Is Not Allowed’

pyqgisqgis-3qgis-processing

Hi everyone I'm in some way new with PyQGIS and I've been trying to run a script in QGIS 3.0 without success (it prefectly ran in 2.18) and always get the same error:

AttributeError: module 'processing' has no attribute 'runalg'
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "C:\PROGRA~1\QGIS3~1.0\apps\Python36\lib\code.py", line 91, in runcode
exec(code, self.locals)
File "", line 8, in
TypeError: catching classes that do not inherit from BaseException is not allowed

Does this has something to do with PYTHONPATH? I can't even see the list of algorithms when typing: processing.alglist()

Best Answer

In QGIS 3, use processing.run.

For instance:

QGIS 2.x processing.runalg('gdalogr:convertformat', ...

QGIS 3.0 processing.run('gdal:convertformat', ...

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        'METHOD':0,'COLUMNS':2487,'ROWS':929,
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After trying another input-type, it worked

for f in points_lyr.getFeatures():
    if f.attribute('Art') == 2:
        #pStart = QgsPointXY(f.geometry().asPoint().x(), f.geometry().asPoint().y())
        pStart = str(f.geometry().asPoint().x()) + ',' + str(f.geometry().asPoint().y())
    else:
        continue

for f in points_lyr.getFeatures():
    if f.attribute('Art') == 4:
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parameters = {'INPUT': network_lyr,
                'STRATEGY': 0,
                'DIRECTION_FIELD': '',
                'VALUE_FORWARD': '',
                'VALUE_BACKWARD': '',
                'VALUE_BOTH': '',
                'DEFAULT_DIRECTION': 2,
                'SPEED_FIELD': '',
                'DEFAULT_SPEED': 1,
                'TOLERANCE': 0,
                'START_POINT': pStart,
                'END_POINT': pStop,
                'OUTPUT': 'memory:'}

So it does not work in the first run, when I use QgsPointXY, but it works when the input is a string. Don't know why, but I can work with strings as well.

Best Answer

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