gvSIG-Desktop 1.12. Manual de usuario
If you select the “Union” option, the following dialogue appears:
When you have selected the input layer, the clip layer and an output layer, click on "Ok".
The result layer will have all the intersections and differences between the two layers. If you click on the “Information” button and then on the different polygons in the result layer, you will see that the intersections have all the attributes, whilst the differences only have the attributes of the layer that created them.