If I understand you correctly, v.hull might help to create the service area polygon from the points....
http://grass.itc.it/grass62/manuals/html62_user/v.hull.html On Sun, Apr 4, 2010 at 8:12 PM, Richard Chirgwin <[email protected]> wrote: >> >> ------------------------------ >> >> Message: 3 >> Date: Sat, 03 Apr 2010 23:11:26 +0200 >> From: "Johannes Sommer" <[email protected]> >> Subject: [GRASS-user] v.net.iso - service area >> To: [email protected] >> Message-ID: <[email protected]> >> Content-Type: text/plain; charset="iso-8859-1" >> >> Hi list, >> >> recently I played around with the network functionality in ArcGIS. I >> generated so called "Service Areas" in a network dataset which return the >> regions that can be accessed in a network dataset based on several distances >> (in my example 150, 400 meters). >> >> I wanted to reproduce the results with GRASS GIS and after a short search >> I found the module v.net.iso which seemed to fit my needs. It returns >> exactly the same results as ArcGIS did on isolines on a network, but I can't >> find any solution concerning the service areas. >> >> Can anyone point me in the right direction to calculate zones (that is >> "build polygons from the end points of each network segment") from these >> generated isolines in a network? >> >> Regards, >> >> Johannes >> >> >> > > Johannes, > > I don't think there's anything to do this automatically in Grass-GIS. But I > think you should be able to construct a script that would connect pairs of > points. > > So if you can extract each end point of the network segment, you would end > up with a vector containing only points - then create a temporary map of a > point pair, run (say) v.distance output=connectors on each point pair, patch > the resulting maps together ... > > It sounds a bit labourious, and probably someone else can think of something > easier, but if you get all the individual steps right, a script is then easy > to create. > > (Actually, Johannes, I think the idea is brilliant. I've done lots of > network service area work, and it never occurred to me before!) > > Richard Chirgwin > > _______________________________________________ > grass-user mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/grass-user > _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
