I'm new to desktop GIS, and will try to ask while lacking the proper terms from the GIS lingo:
If QGIS was like Photoshop I would like to make a selection from one layer, and then match that selection to another layer to get the overlap between the two and create a new layer from this overlap.
Formulated in another way:
I want to select all land from each of the Norwegian municipalities. In the shape-file I have (you can download it here: http://www.statkart.no/?module=Files;action=File.getFile;ID=41973) municipality borders are found as "N5000_AdministrativGrense" (just the borders) and "N5000_AdministrativFlate" (borders and the land within each municipality). This data (borders and land per municipality) is too administrative - it includes ocean and we have a lot of fjords in Norway. I need the landmass minus ocean.
The landmass is found in the layer "N5000_ArealdekkeFlate" - or so it looks to a novice at least.
So - I want to find the intersection between the landmass (only land, no ocean) and municipality borders and make a new layer that is all municipalities without ocean.
I'm on a mac with QGIS as my installed tool. All tips, pointers and help is much appreciated.