On Tue, Oct 4, 2016 at 5:09 PM, Sam Snellings <[email protected]> wrote: > I've been running some trials through v.net.alloc using town road networks > as the arc layer and schools as the node layer. I have one set of > roads/schools that breezes through v.net.alloc without issue (Town 1), while > another one only allocates the first few arcs connected to each school and > leaves the rest of the network unallocated (Town 2). There is probably a > problem with the data from Town 2, but I can't figure out what it is. Does > this issue sound familiar to anyone? > > I am using the GUI. I load each pair of shapefiles into GRASS and then run > the following statements (I only import two school points to simplify). The > two towns are pulled right from the state-wide GIS office, but the towns are > in different states (ie - different agencies provide the data). > You do not need this for v.net.alloc: > v.net input=roads output=road_nodes operation=nodes it will create a point for every node, the first point will have cat=1, the second cat=2 which collides with the points you want to attach
> v.net input=road_nodes points=schools output=network operation=connect > thresh=1000 rather use v.net input=roads points=schools output=network operation=connect thresh=1000 > v.net.alloc input=network output=network_allocation ccats=1-2 the real problem is probably a data problem: roads are not properly connected, i.e. the end of one road does not match the beginning of another road. Try v.clean input=roads output=roads_snap -c tool=snap with a very small threshold. This kind of error is quite common with shapefiles (not a fault of the shapefile format but of the software used to create the shapefiles). > > Thanks in advance for any advice, I can also email images/data if that would > be helpful. If v.clean -c tool=snap does not help, (links to) original data of the schools and road network for Town 2 would be helpful (data please only off-list). Markus M _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
