Thank you Moritz! Of course, v.reclass does the job. I just didn't see the column option...
Regarding the second (additional) part of this question: It seems that v.to.db works well to report line lengths on a category-base. However, sinuosity seems to be calculated based on features (i.e. feature ids). Thus, I only get reasonable results if a cat only consists of one feature. For connected lines that consist of more than one feature (lines) the sinuosity index is not correct. So, I probably need to loop over the cats, extract the lines that belong to one cat and build a polyline before calculating sinuosity. /J On Sun, Sep 17, 2017 at 3:53 PM, Moritz Lennert < mlenn...@club.worldonline.be> wrote: > > > Le 17 septembre 2017 15:16:02 GMT+02:00, Johannes Radinger < > johannesradin...@gmail.com> a écrit : > >Hi, > > > >how can I merge multiple lines into one category based on some > >attribute > >information. > >For example I have a line vector consisting of 10 lines and several > >lines > >belong to three different groups (lines belonging to the same group > >share > >the same value in a specific attribute column). Now I'd like to merge > >them > >(assign a common cats) and create an new attribute with the "group > >value" > >as new category (the table should then have 3 rows)? I think this > >should be > >easily possible, but I could not yet find the correct tool. > > Try v.reclass. > > > Moritz >
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