clip one layer with the current map layers

Question

I work in a little companie where the main goal of employees in GIS is to have a quick view of the issues on a study area.

It would be very useful to have a tool wich clip all the layers of the current map extent with the study area.

I made a quick search in ogr tools but I didn't find the appropriate one. Plus, I think that ogr can't work automatically with the current layers.

So I think the solution is Pyqgis but I have no skills in Python.

Is there an existing tool ? Any suggestions to find the simpliest way to do that ?

Thanks

Answer 1

More specifically, if you have in spatialite a polygon layer "study_area" and another polygon layer "issue", then you would do:

Create a new table for the clipped issue

CREATE TABLE issue_clipped (pk_uid integer primary key autoincrement, 
   issue_name text,
   <any additional fields you need from the issue table> )

SELECT AddGeometryColumn('issue_clipped','geometry',<the CRS id>, 'POLYGON', 'XY');

Now populate the new issue_clipped table as follows:

INSERT INTO issue_clipped (issue_name, geometry)
SELECT issue_name, ST_INTERSECTION(issue.geometry, study_area.geometry)
FROM issue, study_area
WHERE ST_Intersects(issue.geometry, study_area.geometry);