[GRASS-user] v.dissolve for lines?

Martin Landa landa.martin at gmail.com
Wed Oct 20 07:09:50 EDT 2010


Hi,

2010/10/20 Markus Metz <markus.metz.giswork at googlemail.com>:
> v.build.polyline works as follows:
> it picks a line and from its start node, walks back as long as exactly
> one other line is connected to this node. Line directions are reversed
> as required, i.e. it does not matter if the next line is connected to
> the current node by its start or end node.
>
> Once the start line of a polyline is identified, it walks forward and
> adds all vertices (in reverse order if needed) of connected lines to
> the start line, i.e. the start line and connecting lines are reversed
> as needed. That is, if a line is reversed depends on what node is
> initially picked for building polylines.
>
> If the direction of lines is important (it's not for boundaries to
> build areas), you have to manually change line directions with either
> v.edit or the wxdigitizer or the tool by Maris.

I took a liberty to add your useful notes to v.build.polylines manual - r43979.

Martin

-- 
Martin Landa <landa.martin gmail.com> * http://geo.fsv.cvut.cz/~landa


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