Re: [udig-users] shape file representation

[andrea antonello <andrea.antonello@xxxxxxxxx>]

> Another technique would be to do this with a style.
>
> If you use a point symboliser it will draw the centred of each polygon. You
> could then make a formula based on the population size for the point
> symboliser size.
>
> perhaps: 256.0*(POPULATION / 8000000000.0)

I think what you are saying is possible only the way I proposed it.
We have no way to add a point sybolizer to the polygon layer, so first
he has to create a point layer (centroid) and the rest is the same as
my workflow, right?

Andrea


>
> --
> Jody Garnett
>
> On Saturday, 5 May 2012 at 3:34 PM, andrea antonello wrote:
>
> Hi,
>
> I have a shape file with polygon, in my attributes I have the population of
> each polygon.
> I would like to have a representation where I can see the polygon and, one
> circle representing the population for one polygon .
> It should be like the attached file.
> Is it possible with udig ?
>
>
> right now I think you would need a step for getting the shown result.
>
> That is what I would do:
> - create a layer of the baricenters of the polygons (we will use a
> points layer) -> reshape operation, see:
> http://udig.refractions.net/confluence/display/EN/Constraint+Query+Language
> for the functions you can use
> - in the same operation I also would create a new field that
> normalizes the population value (you will use that as field that
> defines the size of the point)
>
> So the reshape operation would look like:
>
> the_geom=baricenter(the_geom)
> size=population/maxvalue
>
> That will create you a new layer that will then produce the style you want.
>
> Jody is working a lot on reshape and filters these days, so it might
> already be easier.
>
> Cheers,
> Andrea
>
>
>
>
> best regards
> Thomas
>
> --
> Thomas DOLLEY
> Projet GUYASIM
> UMR ECOFOG
> Bātiment D
> TA C-105 / D Campus international de Baillarguet 34398 Montpellier Cedex 5
> France
> Tél : +33 4 67 59 38 85
>
>
>
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