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I am trying to perform a feature selection on qgis similar to "add to current selection" interactive selection method in Arcgis Desktop, is that possible?

An example: I perform a spatial query and select a set of features, afterwards I need to manually add a couple of features to this set, if I use the feature selection button I lose my first selection, and start a new one.

Any way of adding features to a selection? Many thanks everyone in advance,

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    You can hold the Control key when clicking the desired features. Is that what you mean? – Jake Oct 25 '13 at 10:11
  • Thanks Jake,that won't work in this case (I've already tried), as I am doing a spatial selection first and am trying to add features to my selection afterwards – Guillermo Oct 25 '13 at 11:54
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You can do it in several different ways. Assuming you already have a selection, you can add new feature to your selection by:

  • Select them interactivelly with any of the selections tool(Rectangle, Polygon, freehand), pressing "Ctrl" or "cmd" (Like jake already said). Take notice that if you select a already selected feature, it will be unselected;

enter image description here

  • If you wish to add features by a new spatial query, in the spatial query plugin you can use "add to current selection" in the "And use result to" option;

enter image description here

  • You can also use the "Select Feature by using an Expression" tool, create a desired expression and use the "add to selection" option;

enter image description here

Note 1: In all methods, the active layer must be the one you need to add or remove features from selection;

Note 2: You can use the same methods to remove a few features from the current selection.

Hope it helps!

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  • "Add to current layer" should probably be "Add to current selection" :) – Matthias Kuhn Oct 25 '13 at 11:09
  • thanks a lot, but I knew those methods. The point is selecting features by one of these functions (spatial, expression), keeping the selection, maybe look up statistics of the selected features, and, later, perform a new selection (point, rectangle tipically, but could be spatial or expression). I want this new selection to add up to the first one, instead of "replacing" it. – Guillermo Oct 25 '13 at 11:59
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    If you follow my instructions, all methods add features to the current selection. I have updated the answer to highlight the important parts of using the selection tools to get what you need. If this does not work for you, then I don't understand your question. – Alexandre Neto Oct 25 '13 at 12:52
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    Alexandre, I can do many kinds of selections with your methods, and using them I will manage to do this job. But what I intend and can´t is adding a manual selection (or multi-selection via CTRL) to a previous spatial or expression selection. CTRL wouldn't work, and there is no 'add to selection' option. Thanks a lot anyway for your answer, which is really complete and clear. – Guillermo Oct 28 '13 at 7:24
  • @Guillermo, that is strange, I can add features to the selection by holding CTRL (it works as if it is a "add to selection" option). What version of QGIS are you using, and in what platform? – Alexandre Neto Oct 28 '13 at 9:34
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Just in case someone else should come across this question and wonder why the Ctrl key modifier doesn't work..

As pointed out in a related answer:

in 2.18, holding Shift adds features, while Ctrl removes features

This is works the same way in QGIS 3.0

(Though I think the "add to current selection" is the ultimate solution to the algebra.)

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