You could generate a standard 30km buffer using the buffer tool in Vector > Geoprocessing Tools > Buffer.
Then create an extent polygon from that output buffer using Vector > Research Tools > Polygon from layer extent. I'm curious of the extent polygon is going to retain the 30km distance though.. Something to test out =) On Mon, Mar 11, 2013 at 1:42 PM, Bernd Vogelgesang <bernd.vogelges...@gmx.de> wrote: > >> Dear all, >> I have a point (from a shapefile) and I need to create a squared buffer, >> centered on my point with a distance of 30 kms. How can I do this in QGIS? >> Thanks >> Regards, >> Luisa > > > I would: > - add geometry column to that point > - open dbf as spreadsheet > - calculate 4 new coordinate pairs in thr rows below (Xmax/Ymax, Xmax,Ymin, > Xmin/Ymax, Xmin/Ymin), where max= x+30000 and min = x-30000 (if this is a > metric system) > - save that to a csv-file and import with Add Text Delimited Layer > - now you have the corner points, create a polygon layer and digitize a > polygon with snapping to the point layer. > > There might be numerous ways to do that, but thats what first came to my > mind. > > Bernd > -- > _______________________________________________ > Qgis-user mailing list > Qgis-user@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/qgis-user _______________________________________________ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-user