fTools:Select by location is confusing, especially with an empty selection

[qgib]

Author Name: Leyan Ouyang (Leyan Ouyang)
Original Redmine Issue: 6018
Affected QGIS version: master
Redmine category:processing/qgis

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I used "Select by location" in the fTools plugin, with the options to use selected features only. The progress bar started the movement left and right used for an unknown amount of remaining time, so I waited, surprised that my small data set was so hard to select.

Actually, the selection was empty and no calculation was happening, but it took me the longest time to realize it. The problem is twofold:

• nothing prevents using an empty selection (even if it cannot be useful), but self.progressBar.setMaximum(len(features)) on line 114 of doSelectByLocation.py does not have the expected result when features is an empty list as it makes an endlessly moving progress bar
• More globally, the plugin doesn't indicate anything when the computation is finished. I would have expected either closing the window or at least showing a message indicating the number of selected features. Something like: "%d features have been selected, the existing selection had %d features, the new selection has %d features" % (nbSelected, nbPrevious, nbEndResult) ))@ at the end of the compute() function

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• qgis_select_by_location.mkv (Leyan Ouyang)

[qgib]

Author Name: Paolo Cavallini (@pcav)

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• fixed_version_id was configured as Version 2.0.0

[qgib]

Author Name: Giovanni Manghi (@gioman)

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The first issue does not seems to happen (anymore).

About the second suggestion, the number of selected features is shown in the left bottom corner of the main qgis window.

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• status_id was changed from Open to Closed
• fixed_version_id was changed from Version 2.0.0 to Future Release - Nice to have
• resolution was changed from to worksforme

[qgib]

Author Name: Leyan Ouyang (Leyan Ouyang)

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The problem still exists in the latest Master build. Clear all selection, start "select by location" tool, check the "use selected feature only" (I agree it does not make sense, but one can check it by mistake like I did the first time). Then when starting the process no actual computation happens (well, there aren't any feature to consider) but the progress bar is continuously moving, which is very misleading.

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• status_id was changed from Closed to Reopened

[qgib]

Author Name: Giovanni Manghi (@gioman)

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Leyan Ouyang wrote:

The problem still exists in the latest Master build. Clear all selection, start "select by location" tool, check the "use selected feature only" (I agree it does not make sense, but one can check it by mistake like I did the first time). Then when starting the process no actual computation happens (well, there aren't any feature to consider) but the progress bar is continuously moving, which is very misleading.

I tested another dataset and still works fine here. If there are no features selected and then the "use selected features only" is checked, then the tool works as it is expected (at least for me)... using all features to make the selection.

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• status_id was changed from Reopened to Feedback

[qgib]

Author Name: Leyan Ouyang (Leyan Ouyang)

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Sorry, I forgot to provide feedback about this bug. Here is a screencast of what I mean.

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• 6232 was configured as qgis_select_by_location.mkv

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• qgis_select_by_location.mkv (Leyan Ouyang) - screencast

[qgib]

Author Name: Giovanni Manghi (@gioman)

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Ok, now I see it.

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• status_id was changed from Feedback to Open
• priority_id was changed from Normal to Low
• resolution was changed from worksforme to

[qgib]

Author Name: Alexander Bruy (@alexbruy)

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Does not happen anymore with Processing. Please reopen if necessary

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• status_id was changed from Open to Closed

[qgib]

Author Name: Giovanni Manghi (@gioman)

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The "ftools" category is being removed from the tracker, changing the category of this ticket to "Processing/QGIS" to not leave the category orphaned.