I have a shapefile which contains all German Zip-Codes in a a five-digit format (e.g. 80637). For what I intend to do, this is way to much detail. I would like to aggregate all Zip-Code areas by the first two digits (e.g. 80).
My approach is ordering ZIP codes in the QGIS attributes table numerically, then selecting them manually, then joining them. This is somewhat cumbersome I'll have to do this a hundert time.
Is there a way of doing this programmatically? I tried automate this process following this instruction, but I failed at importing sextante.