[Qgis-user] Drawing over lapping polygons from postgis vector data table.

[Andre Joost]

Am 13.11.2014 um 10:34 schrieb Dave Potts:
> Hi
>
> I am trying to display the results of a spatial analysis, the return
> form is a set of polygons of increasing size. All located on top of each
> other.  I want to draw it, so it looks like a target, but all that
> happens is that the largest polygon is drawn last which blocks out all
> of the others.  Is there an easy way of display the result?
>
> I can not see any way of using an outside function so that the largest
> polygon would be drawn firsts with the next polygon drawn on top of it.
>
> Since its an import from a postgis table every does have an unique id.
>

In Layer Properties, Style tab you can use a categorized or graduated 
style based on the unique id, or some other field of the attribute table.

Then click on the "Advanced" button beneath the symbol table, and select 
"Symbol levels". If you check "Enable symbol levels", you can predefine 
in which order your symbols should be rendered.

You can even set all colours equal or a fill style "No Brush" if you 
only want to see the contours.

HTH,
André Joost