v.net.curvedarcs - GRASS GIS manual

Note: This addon document is for an older version of GRASS GIS that will be discontinued soon. You should upgrade your GRASS GIS installation, and read the current addon manual page.

NAME

v.net.curvedarcs - Draws curved arcs between points (e.g. flows)

KEYWORDS

vector, network, flows

SYNOPSIS

v.net.curvedarcs

v.net.curvedarcs --help

v.net.curvedarcs [-s] input=name [layer=string] flow_input_file=name [separator=character] output=name minimum_offset=float maximum_offset=float [vertices=integer] [--overwrite] [--help] [--verbose] [--quiet] [--ui]

Flags:

-s: Draw also short line for flow from and to same node
--overwrite: Allow output files to overwrite existing files
--help: Print usage summary
--verbose: Verbose module output
--quiet: Quiet module output
--ui: Force launching GUI dialog

Parameters:

input=name [required]: Point map containing origins and destinations; Or data source for direct OGR access
layer=string: Layer number where to find point categories; Vector features can have category values in different layers. This number determines which layer to use. When used with direct OGR access this is the layer name.; Default: 1
flow_input_file=name [required]: File containing origins, destinations and flow volumes; Name of input file
separator=character: Separator used in input text file; Special characters: pipe, comma, space, tab, newline; Default: pipe
output=name [required]: Output map with curved lines; Name for output vector map
minimum_offset=float [required]: minimum offset at furthest point from straight line
maximum_offset=float [required]: maximum offset at furthest point from straight line
vertices=integer: number of vertices used to draw curved lines; Default: 30

DESCRIPTION
NOTES
EXAMPLE
SEE ALSO
AUTHORS

DESCRIPTION

v.net.curvedarcs is a frontend to v.net and v.segment that creates curved arcs between given start and end points. The user provides a point vector map and a text file (see Notes section) with start and end point categories as well as a flow volume for this link which will be transferred to the attribute table of the curved arcs.

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.

NOTES

EXAMPLE

TODO

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

The curved arcs with minimum offset = 150 and maximum offset = 2000

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

The curved arcs with minimum offset = 0 and maximum offset = 5000

AUTHORS

Moritz Lennert, DGES-ULB

SOURCE CODE

Available at: v.net.curvedarcs source code (history)

Latest change: Mon Jun 28 07:54:09 2021 in commit: 1cfc0af029a35a5d6c7dae5ca7204d0eb85dbc55