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NAME
v.net.iso - Splits net by cost isolines.
Splits net to bands between cost isolines (direction from centre). Centre node must be opened (costs >= 0). Costs of centre node are used in calculation.
KEYWORDS
vector, networking
SYNOPSIS
v.net.iso
v.net.iso help
v.net.iso [-g] input=name output=name [type=string[,string,...]] [alayer=integer] [nlayer=integer] [afcolumn=name] [abcolumn=name] [ncolumn=name] ccats=range costs=integer[,integer,...] [--overwrite] [--verbose] [--quiet]
Flags:
- -g
- Use geodesic calculation for longitude-latitude locations
- --overwrite
- Allow output files to overwrite existing files
- --verbose
- Verbose module output
- --quiet
- Quiet module output
Parameters:
- input=name
- Name of input vector map
- output=name
- Name for output vector map
- type=string[,string,...]
- Arc type
- Options: line,boundary
- Default: line,boundary
- alayer=integer
- Arc layer
- A single vector map can be connected to multiple database tables. This number determines which table to use.
- Default: 1
- nlayer=integer
- Node layer
- A single vector map can be connected to multiple database tables. This number determines which table to use.
- Default: 2
- afcolumn=name
- Arc forward/both direction(s) cost column (number)
- abcolumn=name
- Arc backward direction cost column (number)
- ncolumn=name
- Node cost column (number)
- ccats=range
- Category values
- Categories of centres (points on nodes) to which net will be allocated. Layer for this categories is given by nlayer option.
- costs=integer[,integer,...]
- Costs for isolines
DESCRIPTION
v.net.iso splits net to bands between cost isolines (direction from
centre). Centre node must be opened (costs >= 0). Costs of centre node are
used in calculation. Supported are cost assignments for both arcs and nodes,
and also different in both directions of a vector line. For areas cost will
be calculated along boundary lines.
NOTES
Nodes must be on the isolines.
Center nodes have to be assigned to vector nodes. Nodes and arcs can be closed
using cost = -1.
EXAMPLE
Subdivision of a network into areas:
The map must contain at least one center
(point) on the vector network which can be patched into with
v.patch.
# Spearfish
# start node:
echo "591280.5|4926396.0|1" | v.in.ascii out=startnode
g.copy vect=roads,myroads
#connect point to network
v.net myroads points=startnode out=myroads_net op=connect thresh=200
g.region vect=myroads_net
d.mon x0
d.vect myroads_net
d.vect myroads_net col=red icon=basic/triangle fcol=green size=12 layer=2
v.category myroads_net layer=2 op=print
# specify range of center cats (easier to catch all):
v.net.iso input=myroads_net output=myroads_net_iso ccats=1-100000 costs=1000,2000,5000
v.category myroads_net_iso option=report
# ... reports 4 categories:
The network is 4 categories:
cat | distance from point
1 0 - 1000
2 1000 - 2000
3 2000 - 5000
4 > 5000
To see the result, run for example:
g.region n=4928200 s=4922300 w=589200 e=596500
d.erase
d.vect myroads_net_iso
d.vect myroads_net_iso col=blue cats=1
d.vect myroads_net_iso col=green cats=2
d.vect myroads_net_iso col=orange cats=3
d.vect myroads_net_iso col=magenta cats=4
d.vect myroads_net col=red icon=basic/triangle fcol=green size=12 layer=2
SEE ALSO
d.path,
v.net,
v.net.alloc,
v.net.path,
v.net.salesman,
v.net.steiner,
v.patch
AUTHOR
Radim Blazek, ITC-Irst, Trento, Italy
Documentation: Markus Neteler
Last changed: $Date: 2007-08-03 05:33:14 -0700 (Fri, 03 Aug 2007) $
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