Hi,
I'm battling finding an easy way to cut some lines with a polygon boundary, and then deleting the line portions that are OUTSIDE the polygon.

Scenario:

   4 separate SHAPE files with lines in them
   1 shapefile with one polygon in it.

I need to cut the lines in all 4 shapefiles at the point that their lines intersect the polygon boundary. Thereafter I want to delete the line portions that are outside of this polygon boundary. In other words, to be able to crop multiple layers according to some polygon boundary.

I would have thought this to be a trivial issue, but I have tried:

     * Vector Geometry Processing Clip, but it wants to extract the
       data inside the polygon and create a new file with the extracted
       data. (To be expected)
     * Plugin 'Clipper': I select my lonely polygon, and then activate
       one of the line layers (which is also in edit mode).
       The plugin seems to do nothing when I choose 'intersection' or
       'clipping' preview, and when I choose 'clip' it tells me to
       select at least one feature (but my polygon is still selected.)
       The home-page link comes up as '404 not found'
     * Didn't notice anything in the Advanced Digitizing plugin.
     * CadTools and CadDigitize - no relevant facility found,  but
       really nice 'Help' doc - thanks guys!
     * Feature 'Cut with Polygon from another Layer' deletes the pieces
       I want to keep.
     * Feature: 'Split selected features with line from another layer'
       is to some extent what I want, but I want '... with polygon from
       another layer'

So, I eventually gave up and converted my polygon into a line layer, and used 'Split selected features with line from another layer', but this is incredibly tedious because:

 * It only does one layer at a time
 * I then have to select the line segments that I want to delete.


So, does anyone know of a way to efficiently cut features in multiple layers using a polygon, and then to be able to select the pieces (multiple layers) that are either inside or outside the polygon, and then delete them?

Regards & thanks in advance,
Zoltan


--

===========================================
Zoltan Szecsei PrGISc [PGP0031]
Geograph (Pty) Ltd.
GIS and Photogrammetric Services

P.O. Box 7, Muizenberg 7950, South Africa.

Mobile: +27-83-6004028
Fax:    +27-86-6115323     www.geograph.co.za
===========================================

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