Michael Barton wrote > Hi Markus, > > What I'm trying to do is start > http://grasswiki.osgeo.org/wiki/AddOns/GRASS7/vector#v.fixed.segmentpointsa > raster stream map from r.drain and convert it to a sequence of vector > points, where each point has information as to its position along the > stream. I then use the points for sampling a stream profile and related > information. Oddly enough, with all of the very useful stream analysis > modules, there is nothing I could find to generate the data for a stream > profile (distance from outlet or from headwaters vs. elevation). > > v.to.points does a nice job of creating a sequence of evenly spaced points > with information about their location along a line (the "along" field). > BUT, if the line is composed of multiple segments or even if it has an > irregularity in it, the "along" values start over again from 0. The only > way I can use it is if I have a very clean and continuous vector line with > only a single cat. > > This has proven surprisingly difficult to obtain reliably from my raster > stream map. So far, the only way has been to do a two sequences of v.clean > (with thresholds 1.5 X the raster resolution) and v.build.polylines. If > you have any better suggestion, I'd love to hear it. > > Thanks again for the polylines idea. That was a big help. > > Michael > ____________________ > C. Michael Barton > Director, Center for Social Dynamics & Complexity > Professor of Anthropology, School of Human Evolution & Social Change > Head, Graduate Faculty in Complex Adaptive Systems Science > Arizona State University > > voice: 480-965-6262 (SHESC), 480-965-8130/727-9746 (CSDC) > fax: 480-965-7671 (SHESC), 480-727-0709 (CSDC) > www: http://www.public.asu.edu/~cmbarton, http://csdc.asu.edu > > > > >> On Nov 29, 2014, at 10:20 AM, Michael Barton <
> Michael.Barton@ > > wrote: >> >> Thanks. This helped. >> >> Michael >> ____________________ >> C. Michael Barton >> Director, Center for Social Dynamics & Complexity >> Professor of Anthropology, School of Human Evolution & Social Change >> Head, Graduate Faculty in Complex Adaptive Systems Science >> Arizona State University >> >> voice: 480-965-6262 (SHESC), 480-965-8130/727-9746 (CSDC) >> fax: 480-965-7671 (SHESC), 480-727-0709 (CSDC) >> www: http://www.public.asu.edu/~cmbarton, http://csdc.asu.edu >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >>> On Nov 29, 2014, at 1:23 AM, Markus Neteler < > neteler@ > > wrote: >>> >>> On Sat, Nov 29, 2014 at 6:16 AM, Michael Barton < > Michael.Barton@ > > wrote: >>>> I have a vector line that is divided into 12 cat values. I’d like all >>>> of the >>>> line to have a single cat value. I’ve tried v.category to no avail. If >>>> I >>>> delete all categories and then add new categories, I get 12 cats again. >>>> And >>>> I can find no other way to get a single cat for the entire line. >>>> Hopefully >>>> someone can tell what I’m missing here. >>> >>> Please try to use >>> http://grass.osgeo.org/grass70/manuals/v.build.polylines.html >>> >>> Markus >> > > _______________________________________________ > grass-user mailing list > grass-user@.osgeo > http://lists.osgeo.org/mailman/listinfo/grass-user for points along a vector with a fixed distance between the points, see the addon http://grasswiki.osgeo.org/wiki/AddOns/GRASS7/vector#v.fixed.segmentpoints ----- best regards Helmut -- View this message in context: http://osgeo-org.1560.x6.nabble.com/how-to-change-all-cats-in-a-vector-line-tp5175575p5175633.html Sent from the Grass - Users mailing list archive at Nabble.com. _______________________________________________ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user