[Qgis-developer] Suppress rendering of small features

[Matthias Kuhn]

Hi,

We just discussed this and concluded, that the safest solution would be 
to only simplify for rendering and only when the resolution is small 
enough, that only points which will be painted on top of each other 
will be simplified away. (And then we should make some tests and see if 
it's actually worth it...)

Matthias

On Fri 13 Sep 2013 04:33:45 PM BST, kimaidou wrote:
> Hi all
>
> I also think dynamic scale-dependent simplification would be very nice
> but for me ONLY if we can preserve topology when simplifying. If not,
> it would lead to very uggly results
> cf http://strk.keybit.net/blog/  for example
>
> +1 for optionnaly remove small feature though, this will be good too !
>
>
> 2013/9/12 Vincent Mora <vincent.mora at oslandia.com
> <mailto:vincent.mora at oslandia.com>>
>
>     Hi,
>
>     I did something somewhat similar to solve #4819 in Jully
>     ("Identify Features"
>     tool is slow with complex/big features) and Matthias asked me to
>     do the
>     same thing for the rubber-band.
>
>     In polygon contours, points that are less than a pixel apart from the
>     previous point are not drawn.
>
>     That improved (dramatically) the rendering speed.
>
>     Vincent
>
>
>     On 12/09/2013 13:03, Sandro Santilli wrote:
>     > On Thu, Sep 12, 2013 at 08:51:43AM +0200, Andreas Neumann wrote:
>     >> Hi,
>     >>
>     >> As I understand, the feature to suppress small/large features
>     would be
>     >> optional.
>     >>
>     >> Another interesting thing would be to simplify features when
>     you zoom
>     >> out. Maybe simplifying would be quicker than rendering thousands of
>     >> unnecessary vertices. Optionally this could also be
>     "outsourced" to the
>     >> database - many databases support simplification on the db level. I
>     >> don't know if it would really speed up things. One would have
>     to test.
>     > I've done this for mapnik and it worked pretty nicely:
>     > http://blog.cartodb.com/post/20163722809/speeding-up-tiles-rendering
>     >
>     > --strk;
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