[Qgis-user] Node Tool - proposing improvements

[Bernhard Ströbl]

Hi Denis,
thanks for answering

Am 26.11.2018 um 14:00 schrieb Denis Rouzaud:
> Hi all,
> 
> Thanks a lot for summarising this all.

Basically I was reviewing all related issues to see which need to be 
fixed, thus I really played a lot with the new node tool.

> 
> All these issues seem very valid to me, but the logic of bringing back the
> selection of the feature has no valid reasoning to me.
> 
> I see a few things that could be improved to solve these issues:
> 
> 1) choosing/adding vertex in a dense area:
> We could introduce a feature-locking: whenever you have highlighted a
> feature, pressing ALT would lock the feature. That would allow you to
> safely add/choose/move a vertex on that feature.

Would do for any feature that highlights in the first place. Problem is 
that you might have to move around the mouse pointer a lot until your 
desired feature highlights and features totally overlapped by others 
might still be more cumbersome. That's where the proposal to switch 
through the features with right clicks brings improvement. Locking the 
feature with ALT would be the same as my choose-proposal but less 
intuitive than a left click.

> 
> 2) Highlighting:
> The fact that the highlighting is disturbing is a bit subjective to me.
> Is it too aggressive? If so, default colour and width could be tuned a bit
> I guess.

This was a point raised in one issue and I agree it is subjective. Maybe 
it is related to the above, that you have to move around the mouse 
pointer a lot and all the times some feature highlights?

> 
> 3) Adding vertex should stay where it was pressed:
> The solution you propose in 13 seems really good to me (double click adding
> leaves new vertex in place).
> 
> 4) vertices not alway highlighted:
> solution proposed in 1) would also tackle this one I think.
> 
> 5) accidental add/move
> I think that this will only be achieved by training. It is indeed a bit
> less intuitive than previous behaviour. 

IMHO the more intuitive a software behaves the better


> But I don't see any way to change this. 

Could you explain why?

> A right click very cancels very quickly anything anyway.
> 
> 6) consistency
> a) moving vertices
> I don't see the inconsistency here. You can select a vertex and move it
> later, similarly to moving several. Moving a single by simply clicking on
> is just a shortcut to me.

agreed, I could live with that

> b) deleting segments vs vertices
> I think that this also comes with training. The reasoning is that you can
> only select vertices and not segments, and you can delete only what has
> been selected. 

If you can only select vertices then the two vertices should be selected 
when the segment has been clicked on.

> You are never selecting a segment (it never comes blue),

Current behaviour is that you "select" the segment and are ready to move it.

> clicking on it is only a shortcut to move it. Is there a need to be able to
> delete segments faster?

We do not know what users do. I personally neither need a way to delete 
two-vertex segments nor to move them faster than the normal way. But the 
current behaviour is kinda "nervous" and if you click in the wrong 
moment you have to abolish your move with a right click and try again.

> 
> I think the vertex tool became very powerful at the cost of a steeper
> learning curve. I would really be in favour of trying these ideas before
> adding a click in all operations with the tool.


regards

Bernhard

> 
> Cheers,
> Denis
> 
> 
> Le lun. 26 nov. 2018 à 07:33, Bernhard Ströbl <bernhard.stroebl at jena.de> a
> écrit :
> 
>> Dear all,
>>
>> I want to apologize, this has become an extremely long mail...
>>
>> A lot of discussion has been going on about the recent reimplementation
>> of the node tool in QGIS 3.
>>
>> I see two reasons for this:
>> 1) The way the tool works is very different from the way it used to work
>> in QGIS 2:
>> a) in QGIS 2 it was choose feature - choose node(s) - do something
>> whereas in QGIS 3 it is choose node - do something
>> b) to move a node was click - (keep pressed) - move - release which was
>> changed to click - release - move - click - release
>> 2) There have been several bugs (as could be expected with a new
>> implementation). These, however, were used to question the whole feature
>> (most of the bugs are fixed now).
>>
>> Apart from bugs and people not being used to the new tool the critics
>> concentrate around:
>> 1) Probably most annoying: Mouse movements for choosing an existing
>> vertex/adding a new vertex at the middle of the line are not well
>> defined (especially important if features and its vertices are very
>> close together). Imagine a polygon surrounded (or even worse:
>> overlapped) by others, now try to click a particular vertex. You will
>> fail if always the neighbouring polygon is highlighted. The workaround
>> is to select the vertex with a mouse window while its feature is
>> highlighted (or previously select the feature e.g. with the
>> Select-Feature tool). For overlapping features it is even harder.
>> 2) Highlighting effect is disturbing.
>> 3) Adding a new vertex puts the new vertex on the mouse ready to be
>> moved but user has no intention to move it but to leave it where it has
>> been added (e.g. for topological reasons).
>> 4) Vertices are not visible all the time but only when the feature is
>> highlighted. This can make choosing a particular vertex difficult (see
>> also 1).
>> 5) It is easy to accidentally add or move a vertex because the most
>> intuitive way of selecting something is to click it. But when you click
>> a vertex/segment/cross while being highlighted you are already on your
>> way to move it.
>> 6) The behaviour is not consistent:
>> a) If you want to move _one_ vertex, try to grab it when it is
>> highlighted then move it; if you want to move several vertices, first
>> select them, then click them, then move them.
>> b) If you want to delete a vertex, try to grab it when it is
>> highlighted; if you want to delete a segment, do not try to grab it when
>> it is highlighted but select its two vertices and delete them.
>>
>> The German user group thinks that the points raised above are valid,
>> even if all pending bugs are fixed. The node tool is still not perfect
>> (it wasn't in QGIS 2 either).
>>
>> So we propose a change in the way the node tool works and would like to
>> hear other users' s opinions.
>> While the click - move - click change has valid reasons (use advance
>> digitizing panel, pan or zoom map while moving vertices) the dropping of
>> the first choose feature - then choose vertex workflow to immediately
>> move a vertex has no real reasoning (except that it is less clicks in
>> those cases where the node can be easily grabbed in the first place).
>> But this new workflow is the main cause for the problems listed above.
>>
>> Therefore we would like to see the old workflow reimplemented with some
>> of the new ideas added plus some new ingredients. This is the draft for
>> how the tool might work in the future:
>>
>> 1) While the mouse is moved around features are highlighted to indicate
>> they can be edited. Furthermore eventual vertices, segments or crosses
>> are highlighted, too (as in QGIS 3).
>> 2) While a feature is being highlighted, it can be chosen with a left
>> click (new).
>> 3) If the user makes a right click instead, another (adjacent) feature
>> is highlighted and can be chosen with a subsequent left click and so on
>> (new).
>> 4) As soon as a feature is chosen, the Vertex-Editor panel is opened (as
>> in QGIS 2).
>> 5) A chosen feature is the only feature whose vertices can be edited at
>> that point* (as in QGIS 2). The chosen feature and all its vertices stay
>> visible until the end of this feature's editing session (as in QGIS 2).
>> If a vertex was highlighted it is immediately selected, if a segment was
>> highlighted, its two vertices are immediately selected, if the middle of
>> a segment was highlighted with a cross a new vertex is created there and
>> immediately selected (new).
>> 6) A vertex is selected by left clicking on it (as in QGIS 2).
>> 7) Several vertices are selected by using a mouse window (as in QGIS 2
>> and 3).
>> 8) A click on a segment selects its two vertices (as in QGIS 2).
>> 9) Vertices can be selected via the Vertex-Editor panel, too (as was in
>> QGIS 2)
>> 10) Every new vertex selection clears any previuos selection except if
>> Crtl is pressed which adds the new selection to the current if vertices
>> were not selected or subtracts them from the current selection if they
>> were selected (as in QGIS 2).
>> 11) Selected vertices can be deleted (as in QGIS 2 and 3).
>> 12) Selected vertices can be moved by clicking either of them, thus the
>> vertex (the vertices) are attached to the mouse and can be dropped with
>> another left click (as in QGIS 3). A right click aborts the moving
>> operation but the vertices are still selected (new).
>> 13) A new vertex can be created by double clicking on any segment (as in
>> QGIS 2 and 3), the new vertex is immediately selected (new).
>> 14) A right click ends the chosen feature's editing session, if another
>> feature is within reach it is immediately highlighted, continue as in 1)
>> (new).
>> 14b) To be discussed: Left clicking another feature immediately chooses
>> this feature (as in QGIS 2).
>>
>> * topological editing is still posssible, of course
>>
>> We see the following advantages in this approach:
>> 1) The new quick editing possibilities are preserved, there is just one
>> additional click (compared to current QGIS 3) to move an existing vertex
>> or segment or to create and immediately move a new vertex.
>> 2) It is easier to create a new vertex in place.
>> 3) It is a lot easier to graphically choose the feature to edit.
>> 4) The highlighting indicates, which feature will be chosen by an
>> immediate click, no surprises for the user.
>> 5) It is easier to graphically select the vertices to edit.
>> 6) The workflow is always the same: Choose feature - select vertices -
>> do something with them.
>> 7) The workflow is consistent with creating a new feature (right click
>> to finish editing).
>> 8) The application is more consistent because graphically selecting
>> vertices works the exact same way as graphically selecting features with
>> the Select-features tool.
>>
>> I appreciate your feedback
>>
>> Bernhard
>>
>>
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>> --
> 
> Denis Rouzaud
> denis at opengis.ch  <denis at opengis.ch>
> +41 76 370 21 22
> 
> 
> 
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> 


-- 
Bernhard Ströbl
Anwendungsbetreuer GIS

Kommunale Immobilien Jena
Am Anger 26
07743 Jena

Tel.: 03641 49- 5190
E-Mail: bernhard.stroebl at jena.de
Internet: www.kij.de


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