3

I have a layer with thousands of points.

enter image description here

I have been asked to represent this layer in way that can be easily seen the level of concentration of points in the layer. So when there is much point concentration, the zone should be darker (or redder i don't mind) and if there are few points the zone should be lighter (or greener).

I don't know exactly how to achieve this but i tried creating a buffer polygon for every point. The problem is that the color in this new layer is not added while elements overlay...

enter image description here

How could i edit the layer's style to achieve so in QGIS?

Another aproach that could be uselful is to obtain a raster image with red zones and green zones depending on the concentraion of points. I prefer to obtain a vector layer but if i can generate both layers better than best.

Regards,

3

What you are looking for here is the blending effects you can do on the vector features.

enter image description here

enter image description here

Example only of course, you can do a lot more with the blending effects. Just play around until you find something that you like.

2

For a raster layer:

you can create a Heatmap (Raster > Heatmaps) which is quite effective in showing concentration differences (note: available to download and install this from the plugins menu if you don't already have it):

Points

Heatmap of points

I used the following style options for the heatmap raster layer:

Heatmap style options

Hope this helps!

  • 1
    Changing the blending mode (under colour rendering in the heatmap style settings) can be useful too. Changing it to 'multiply' will allow landmarks on details on layers to be visible if needed. – Tumbledown Feb 2 '15 at 13:12
  • @Tumbledown, brilliant point! Edited images to reflect your suggestion, thank you! – Joseph Feb 2 '15 at 13:26
  • Most welcome @Egidi, hopefully others can advise on how to do this for a vector layer as I would also find that interesting. – Joseph Feb 2 '15 at 13:42

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