[Qgis-user] how to calculate the overlap area of several polygons of the same shape qgis 2.4

[Siki Zoltan]

Dear Francesc,

Create a unique field in the attribute table of your polygon layer, for 
example an ordinal number of the features ($rownum in field calculator)
Add the same polygon layer twice to your QGIS project. Rename one of them 
not to mix them up. Use the Vector/Geoprcessing/Union (or intersection) 
between the two layers (refering to the same shape file).
In the result you will get the columns of the two layers, names are 
changed to be unique (e.g. if you created an id column, then you get id 
and id_2). You can ignore/delete those polygons where id = id_2.
Add an area column to the result using the field calculator.

I hope it helps you.

Best regards,
Zoltan

On Sat, 11 Apr 2015, Francesc Caas wrote:

> Hi,
> I'm using qGis 2.4 and I want to know the overlap area of many polygons of
> the same shape. How can I do it? There any tool to do it or I have to do
> some steps? There are too many polygons to create separate shapes for
> everyone and make clips.
>
> Thanks a lot.
>
>
>
> -- 
> *Francesc Ca˙˙as <http://francescsig.info/>*
> Ambientoleg SIG <http://francescSIG.info>
> <http://aixonoesunblog.blogspot.com>
>