I have a set of postcode boundary data that currently goes down to the most detailed level possible, like this:
I would like to 'simplify' the data so that it just shows the first part of the postcode, and thus a simpler, higher-level boundary. Essentially I just want:
In MapPublisher, I can import the data, apply a Selection Filter that looks for 'AB1' (for example), and then use Illustrator's pathfinder tool to merge this into one polygon consisting of just the outer boundaries of the smaller constituent polygons.
However, the problem I have is that MapPublisher can't export this data out as a Shapefile.
In Quantum GIS, I can select individual sectors by simply searching for 'AB1' in the attribute table. However, I don't know how to go about A)'merging' the individual areas into the one big shape or B)exporting them all to a new Shapefile.
Can anyone help? Is Quantum the best (free) tool for the job?