[Qgis-developer] Re: Working on Symbology Improvement for the GSOC

[Mayeul Kauffmann]

Hi,
Using QGIS 1.9 I've rendered one third of the Alps with 15 different
zoom levels as a hobby project (and serve the world at work on QGIS
server with a simpler symbology). See links and what I've learned from
this below.

Here would be my wish-list should we want to compete with open renderers
like Mapnik and Osmarender:

- Better (point) displacement plugin and/or rules on how to manage
overlapping symbols (ignore some symbols). For an example of what is
wrong, see here:
http://www.outdoormaps.org/simple_map.htm?zoom=15&lat=46.10527&lon=7.07953&layers=B0


- Manage z-index (show bridges above roads above tunnels above...). (I
proposed a quite simple implementation.)

Here one example where Mapnik gives good results but my (qgis-made)
outdoormaps fails:
http://www.outdoormaps.org/map.htm?zoom=16&lat=45.72481&lon=8.62683&layers=0FFTTTTF

It's a road over a railway over a road. Picture below:
http://fr.structurae.de/photos/index.cfm?JS=170534

OpenStreetMap statistics show that this (and more tricky) examples are
common.

- if/else / priority of rules functionality (as it was in 1.7.4 or with
other implementation)

I have detailed most of those in the thread below:
http://comments.gmane.org/gmane.comp.gis.qgis.devel/17094

Other note: For the "sample dataset" function the user can simply load a
simple dataset and experiment with it, then save the styles and apply
them in another project. I worked with a sample area on an old machine
then applied it to the world (OSM) with success. For average and fast
machines, then the postgis indexes do the workas long as you do not zoom
out too much so live experimentation with OSM world dataset is possible
with QGIS.

Mayeul



Le lundi 02 avril 2012 à 08:14 +0200, Martin Dobias a écrit :
> On Sun, Apr 1, 2012 at 11:49 PM, Tim Sutton <lists at linfiniti.com> wrote:
> > - in the tree, each node should have a small preview icon for that
> > node. So for example if a node is a symbol layer, it would just show
> > that simple line or whatever. If the node is a symbol, it should show
> > the composited result of the symbol layers beneath it. If the node is
> > an aggregate symbol, is should show the composited result of the
> > symbols beneath it.
> > - Assuming a tree that works this way:
> >
> >  - Class Symbol
> >   - Aggregate symbol
> >     - Symbol
> >     - Symbol
> >       - Symbol Layer
> >       - Symbol layer
> > [...]
> >
> > - The gui we had envisaged in Lisbon would provide a tree and to the
> > right of it would be a widget which would update based on the context
> > of the node you are on.
> 
> I have also recalled the GUI brainstorm from Lisbon hackfest - I have
> put together a quick mockup to explain what we designed one year ago.
> The image is attached. Please note that this one dialog should replace
> the recursive series of symbol selector + symbol properties dialogs.
> The idea is that there would be just one dialog for setting symbol
> properties that dynamically updates its content depending on the
> selection within the symbol tree.
> 
> I will comment on other ideas/proposals later.
> 
> Cheers
> Martin
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