[Qgis-developer] Cad-Input for QGIS prototype

Bernhard Ströbl bernhard.stroebl at jena.de
Mon Jan 27 01:52:14 PST 2014

Hi Antonio and Olivier,

I will comment below.
Olivier, thanks for the move.

Am 26.01.2014 06:05, schrieb Antonio Locandro:
> Hi Oliver, thanks for copying me in this email
> Let me tell you that I have installed your prototype and tested it. I do
> think something like this is needed and I do like the fact that it works
> with other tools directly. I like the fact it gives you guidelines of
> what it will do like in CAD software. I think it would be nice to add
> also the possibility to use right clicks for actions

I have not tried your plugin but watched the video. Looking at defining 
an angle it should be definable relative to a) the last segment b) North 
c) another (helper) point

> To address your points
> 1) yes this feature is needed in QGIS, other COTS software have this
> functionality as Advanced Editing and I do rely heavily daily on this
> type of things for my job and is amongst several reasons why we cant
> switch for QGIS. I know the main user base of QGIS probably use it only
> for analysis but for some of us we need to digitize precisely
> coordinates based on field data or to create specific features.

would be useful here, too
Although I think most CAD functions for which currently nothing similar 
is available in QGIS are for construction I still think, it would be 
great to have them. (Of course not those to create 3D screws :)

> I would vote to keep to make it part of core as Advanced Tools or
> something, I also think it would be quite nice to merge the different
> CAD-like tools into one and have all this contributors who made this
> individual plugins work as a team. Resources are not always available
> and to join forces to me seems a better approach

The digitizingTools plugin is trying a similar approach, namely to 
combine efforts and present _one_ plugin.

> 2) I would leave that for developers
> 3) I cant code, at least I am not at that level. I am just learning
> python and it might take some time to achieve a level to make something
> useful. I can however test the plugin and suggest features. I think the
> best way is to add issues in the github repository of bugs, improvements
> etc.

I am working more or less continuely on digitzingTools (if need arises). 
I can support in Python coding.

> 4) Some ideas to start with, I will add them to github so you have them
> there also. I understand it is a prototype to see if it gathers traction
> but I feel it will
> - snap to midpoint (snapping options to behave like in CAD software)

more easy control over snapping in general: currently snapping has to be 
set for each individual layer seperately: switch snapping on/off 
completely, set snapping behaviour for all layers at once (segment, 
node), additional snapping options needed: snap to middle of line, snap 

> - Add trim line

trim two lines so they form a corner

> - Add extend line

digitizingTools already offers continuing digitizing of a line (though 
not CAD like in prolonging the line in the direction of its last segment)
would be great to extend several lines until they meet

> - Add ability to create arcs e.g. Tan Tan Radius; select center and add
> radius

question would be how this is to be stored in GIS format

- general: provide a means to move the map while any digitizing tool is 
active. possible solutions
a) shift/ctrl + drag
b) add scrollbars (looks arkward but users at once know what to do)

my 2cts



> - Add the ability to draw by deflection angle apart from perpendicular
> and parallel
> - Maybe add the possibility to add x,y in DMS, DM, DD when working in WGS84
> - The plugin already adds the function to calculate within fields. I
> think one useful thing in length is that by default it is m (or the epsg
> default unit I guess ft might be for some) and that you can add
> different units by adding the appropriate abbreviation like in other
> COTS e.g.
> 18 ft
> 1 NM
> 1 SM
> ------------------------------------------------------------------------
> From: olivier.dalang at gmail.com
> Date: Sun, 26 Jan 2014 03:08:27 +0100
> Subject: Cad-Input for QGIS prototype
> To: qgis-developer at lists.osgeo.org
> CC: diego.gnesi at gmail.com; Stefan.Ziegler at bd.so.ch;
> bernhard.stroebl at jena.de; antoniolocandro at hotmail.com
> Dear list,
> Some times ago, on this list, we discussed[1] about real CAD-like input
> for QGIS, and since I do myself long for such a feature very much, I'd
> like to reopen that discussion by *proposing a python prototype*.
> I know there are already a few plugins aiming in that direction
> (CadTools, ImprovedPolygonCapturing, NumericalInput and a few other).
> They provide the functionality, but not the ease of use you can find in
> CAD packages.
> One key aspect is that they are all specific tools, and do not work with
> other tools directly.
> The prototype is inspired from Archicad's input method which allows to
> combine numeric input with mouse input in a very efficient and flexible
> manner, to get the best of both.
> It is currently very raw and not well tested at all... It also relies on
> a lot of dirty hacks, since the python API is not well suited for this
> type of plugins (have a look at the README on the github page for more
> details).
> *DEMO (video) : https://vimeo.com/85052231*
> *GITHUB (readme, download...) : https://github.com/olivierdalang/CadInput*
> Please, tell me what you think :
> 1) Concept
> - Does this kind of input seem interesting to you ?
> - How does it fit in a GIS-environment ? Since it comes from a CAD
> environment, maybe it's more suited to designing than digitizing.
> 2) API/Core modifications (read
> https://github.com/olivierdalang/CadInput#technical-notes )
> - How do you see the suggested improvements ? Are they feasible ?
> - Does developing this as a python plugin make sense, or does it have to
> be in the core from the start ? (I'm not familiar with core developing)
> 3) Collaboration...
> - Is anyone of you currently working on the same topic ?
> - Would anyone have some time/interest in collaborating on this feature ?
> 4) Other ideas are welcome !
> Thanks for your attention,
> Olivier
> [1]:
> http://osgeo-org.1560.x6.nabble.com/Make-QGIS-interact-with-LibreCAD-td5048565.html
> (To those from this discussion I cc'ed, I though you may be interested,
> I hope you don't mind)
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