[Qgis-developer] FW: Diagram improvements

[Kuhn Matthias, Vermessung]

Oops, clicked the wrong button. Here for the list:


> Hi Marco
> 
> Good thoughts. A dimension more really justifies exponential scaling.
> 
> For diagrams scaled by area, we should then use the specified 
> diameter for the given attribute value and scale other 
> diagrams according to this ratio.
> The other possibility would be to indicate indicate squared units.
> 
> I think the first approach would be better for existing 
> projects, as the reference diagram (specified in the layer 
> config dialog) would keep its original size.
> Whereas the second approach would lead to immediate resize in 
> existing projects but it would be more comprehensible for the 
> user that he is scaling by area.
> 
> --
> Matthias Kuhn
>  
> 
> > -----Original Message-----
> > From: qgis-developer-bounces at lists.osgeo.org
> > [mailto:qgis-developer-bounces at lists.osgeo.org] On Behalf Of Marco 
> > Hugentobler
> > Sent: Friday, August 10, 2012 8:04 AM
> > To: qgis-developer at lists.osgeo.org
> > Subject: Re: [Qgis-developer] Diagram improvements
> > 
> > Hi Matthias
> > 
> > >In my opinion this is a bug in the current version and should be 
> > >changed without option
> > 
> > It will be good to have an additional option to scale 
> proportional to 
> > the area. But I think you should leave the option to scale the 
> > diameter.
> > This was done on purpose, because the diagram size you 
> specify is the 
> > radius, not the area (and this again is similar to the symbology 
> > system, where point symbol size is also diameter, not area). Btw, I 
> > have read that there might also be cases where you want to scale 
> > diagram sizes proportional to the volume (e.g. to display 
> content of 
> > lakes, etc.).
> > 
> > 
> > Regards,
> > Marco
> > 
> > 
> > 
> > Am 09.08.2012 14:48, schrieb Kuhn Matthias, Vermessung:
> > > Do you think circular diagrams (i.e. text and pie) need to
> > have an option to scale their radius instead of their area?
> > > In my opinion this is a bug in the current version and
> > should be changed without option as it overexagerates 
> bigger values. 
> > But maybe there is a reason to leave this choice to the user?
> > >
> > > --
> > > Matthias Kuhn
> > >   
> > >
> > >> -----Original Message-----
> > >> From: qgis-developer-bounces at lists.osgeo.org
> > >> [mailto:qgis-developer-bounces at lists.osgeo.org] On Behalf
> > Of Matthias
> > >> Kuhn
> > >> Sent: Tuesday, August 07, 2012 5:37 PM
> > >> To: Qgis Developer List
> > >> Subject: [Qgis-developer] Diagram improvements
> > >>
> > >> Hi,
> > >>
> > >> I recently started an internship at Uster (a city in
> > Switzerland). My
> > >> job will mostly be to improve QGIS. I'm really looking 
> forward to 
> > >> this great opportunity.
> > >>
> > >> My first job is, to improve the diagrams. Any comments 
> are highly 
> > >> appreciated. (If you think something can be done better
> > differently,
> > >> if you think something is useless, if you are already working on 
> > >> something or you know about somebody already working on
> > something, if
> > >> you wanna say thank you...)
> > >>
> > >> Here a short list of what I've got on my ToDo list.
> > >>
> > >> - Minimum size for diagrams (As an option, scale any
> > diagram smaller
> > >> than...): Done
> > >> - Text diagram: Center text better vertically (As an 
> option): Done
> > >> - Charts are not placed on some polygons (e.g. banana
> > shaped polygons.
> > >> Should this be done with PAL library? Any help appreciated)
> > >> - Ordering: Draw smaller charts on top of bigger one instead of 
> > >> hiding
> > >> (randomly?) colliding diagrams.
> > >> - Make diagrams area accurate! By now the radius instead
> > of area is
> > >> scaled.
> > >> - New diagram type: Bar chart
> > >> - New diagram option: Split diagrams. (Pie charts / Bar
> > charts e.g. 
> > >> age
> > >> pyramid)
> > >>
> > >> If you're interested in the current state of work, have a
> > look at my
> > >> git repo [0] on master. Where it says done in the list above you 
> > >> should be able to check it out.
> > >>
> > >> [0] https://github.com/matthias-kuhn/Quantum-GIS.git
> > >>
> > >> Regards,
> > >> I'm looking forward for comments
> > >>
> > >> Disclaimer: Sorry if you get this topic the second time. 
> I thought 
> > >> I'd written something about it yesterday, but couldn't
> > find it in my
> > >> history nor in the archives, so I'll repeat myself and
> > just believe,
> > >> that I missed the send button when I tried to click it.
> > >>
> > >> _______________________________________________
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> > >> Qgis-developer at lists.osgeo.org
> > >> http://lists.osgeo.org/mailman/listinfo/qgis-developer
> > >>
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> > 
> > 
> > --
> > Dr. Marco Hugentobler
> > Sourcepole -  Linux & Open Source Solutions Weberstrasse 5,
> > CH-8004 Zürich, Switzerland marco.hugentobler at sourcepole.ch 
> > http://www.sourcepole.ch Technical Advisor QGIS Project Steering 
> > Committee
> > 
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