The user can determine the nature of the curve with the minimum_offset and maximum_offset parameters. The longest curve's maximum offset from a straight line is equal to the value of maximum_offset in map units. The other curves maximum offset from a straight line is calulated as length(x)/max_length * max_offset. In other words, shorter lines are less curved than longer lines. However, any line's maximum offset is always at least minimum_offset from the straight line.
v.extract census_wake2000 cat=1,52,70,99,101 type=centroid out=tmp v.type tmp from=centroid to=point out=points echo >> flows.txt << EOF > from,to,volume > 52,1,100 > 1,52,50 > 70,1,50 > 1,70,50 > 99,1,66 > 1,99,100 > 101,1,25 > 1,101,75 > EOF v.net.curvedarcs in=points flow=flows.txt sep=comma out=flows minoff=0 maxoff=2000 d.vect map=flows display=shape,dir width_column=volume width_scale=0.05 size=10 d.vect map=points display=shape,cat fill_color=red icon=basic/circle label_bcolor=black label_size=12 yref=bottom
Using different amount of curvature:
v.net.curvedarcs in=points flow=flows.txt sep=comma out=flows minoff=150 maxoff=5000 --o d.vect map=flows display=shape,dir width_column=volume width_scale=0.05 size=10 d.vect map=points display=shape,cat fill_color=red icon=basic/circle label_bcolor=black label_size=12 yref=bottom
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