It is highly recommended to work with polylines instead of segmented vector lines. The command v.build.polylines creates this map structure.
The lidcol and pidcol columns contain the line IDs which relate mileposts and vector line(s) to each other.
When creating a LRS with this module, any existing rstable will be replaced.
As first step, bus route data are prepared.
# copy into own mapset g.copy roads_net,busroute_tmp d.mon x0 d.vect busroute_tmp # zoom to Spearfish (nord-west city) d.zoom # reduce route map to bus route (reduce to one line) d.extract busroute_tmp out=busroute_tmp2 # vector line needs to be polyline v.build.polylines busroute_tmp2 out=busroute_tmp3 v.category busroute_tmp3 out=busroute op=add g.remove vect=busroute_tmp,busroute_tmp2,busroute_tmp3
g.region vect=busroute n=n+100 s=s-100 w=w-100 e=e+100 d.mon x0 d.vect roads_net d.vect busroute col=red width=2
v.db.addtable busroute col="lid integer" v.db.update busroute col=lid value=22 v.db.select busroute cat|lid 1|22
# generate points map # use d.where to find coordinates along the bus route # use v.in.ascii out=busstops to generate map d.vect busstops icon=basic/triangle col=blue d.vect busstops disp=cat lcol=blue
v.db.addtable busstops col="lid integer, start_mp double precision, \ start_off double precision, end_mp double precision, \ end_off double precision" v.db.update busstops col=lid value=22
v.db.update busstops col=start_mp qcol=cat # verify table v.db.select busstops cat|lid|start_mp|start_off|end_mp|end_off 1|22|1||| 2|22|2||| 3|22|3||| 4|22|4||| 5|22|5||| 6|22|6||| 7|22|7||| # visualize with start_mp to check order d.erase d.vect roads_net d.vect busroute col=red width=2 d.vect busstops icon=basic/triangle col=blue d.vect busstops disp=attr attrcol=start_mp lcol=blue
As second step, the linear reference network is created:
v.lrs.create busroute points=busstops out=route_lrs err=lrs_error \ lidcol=lid pidcol=lid rstable=route_lrs thresh=50
# show LRS table db.select route_lrs d.vect route_lrs col=blue width=2
v.build.polylines, v.lrs.segment, v.lrs.where, v.lrs.label
Last changed: $Date$