Select points from lidar point dataset OUTSIDE a polygon

Discussion created by Luchs on Jul 4, 2013
Latest reply on Jul 5, 2013 by mdenil

I'm struggling with this issue for quite some time now and running out of ideas.
What I want to do is to throw out certain points within a polygon from my entire lidar point dataset (1m resolution). I only want to proceed with the remaining points to interpolate from them z-values within the polygon area.
"Select by location" and switching the selection afterwards doesn't work. No points are selected. I put the point dataset as target layer and the polygon feature as source layer. Using the operation "select by polygon" only gives me rectangular selections of points which cross the polygon (the lidar dataset is presumably merged from several single lidar files to cover the entire basin, maybe that's why).
Clipping the points with the polygon feature works just fine, but what I need is the contrary coverage!
What's the best way to throw out these points and why the selection method does not work?

I hope I made my point clear and someone can help me with this!
Thank you very much!