[Qgis-developer] point displacement renderer plugin

Alex Mandel tech_dev at wildintellect.com
Sat Mar 13 14:00:35 EST 2010

On 03/11/2010 03:30 AM, Marco Hugentobler wrote:
> Hi devs
> Recently, I wrote a plugin to display point datasets where several point 
> features have the same position. With the normal display, it is hard to see if 
> several features overlap.
> The point displacement plugin draws (and optionally labels) such features in a 
> circle around the 'real' position. Background is the need to display where 
> school children live (maybe Andreas could give more details about it).
> My question now is if people think this functionality is of common interest. 
> If yes, then it might be good to add it to core (or as a default plugin). If 
> not, then I could provide a windows dll if there is an interest.
> The plugin sources can be downloaded from:
> www.hugis.net/point_displacement_renderer.tgz
> Looking forward for your feedback,
> Marco

Another use to this type of methodology I saw in use recently is when
working with line layers that are road networks. Sometimes you need
mulitple parrallel lines of differing colors for some segments. Think of
subway, bus or other transit maps where several lines share part of
their routes and you want to show them all together.

An alternative visual to the one you have that might also be useful
would be a clustering algorithm that combines overlapping or neighboring
points into one symbol that automatically scales in size based on the
number aggregated.

Just some ideas.


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