Logical Layer operations : Intersection and Subtraction

[h4ck3rm1k3]

a qgis like logical operations on layers.

be able to subtract two layers from each other so that you can hide features that are in common.
be able to intersect two layers to find common elements.

This could be used to hide administrative borders, if you put them in their own layer and then subtract them.

The subtractions should be only on the screen visible or optionally create a new layer. The subtracted items should not be deleted.

Option to include a buffering to the one layer to operate on all items within an area of one layer.

[h4ck3rm1k3]

For a better definition, by subtraction I mean to find the relative complement of one layer in respect to another :

"The relative complement of A with respect to a set B, is the set of elements in B but not in A"

​http://en.wikipedia.org/wiki/Complement_%28set_theory%29

For buffering see :
​http://en.mimi.hu/gis/buffer.html

These operations are some of the great features in the ftools plugin package for qgis:
​http://www.ftools.ca/

[roberto_nonno]

This is a five year old ticket. Did someone implement anything? It would be an extremely useful tool

[Don-vip]

It would be also almost impossible to do. The logic involved would be way too complex.