## NAME

d.path - Finds shortest path for selected starting and ending node.

## KEYWORDS

display, network, shortest path

## SYNOPSIS

d.path
d.path --help
d.path [-gb] map=name [arc_type=string[,string,...]] coordinates=x1,y1,x2,y2 [arc_layer=string] [node_layer=string] [arc_column=string] [arc_backward_column=string] [node_column=string] [color=string] [highlight_color=string] [bgcolor=string] [--help] [--verbose] [--quiet] [--ui]

### Flags:

-g
  Use geodesic calculation for longitude-latitude locations
-b
  Render bold lines
--help
  Print usage summary
--verbose
  Verbose module output
--quiet
  Quiet module output
--ui
  Force launching GUI dialog

### Parameters:

map=name [required]
  Name of vector map
  Or data source for direct OGR access
arc_type=string[,string,...]
  Arc type
  Options: line, boundary
  Default: line,boundary
coordinates=x1,y1,x2,y2 [required]
  Starting and ending coordinates
arc_layer=string
  Arc layer
  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
node_layer=string
  Node layer
  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: 2
arc_column=string
  Arc forward/both direction(s) cost column (number)
arc_backward_column=string
  Arc backward direction cost column (number)
node_column=string
  Node cost column
color=string
  Original line color
  Default: black
highlight_color=string
  Highlight color
  Default: red
bgcolor=string
  Background color
  Default: white

## DESCRIPTION

d.path enables shortest path vector networking. Costs may be either line lengths, or attributes saved in a database table. 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.

## NOTE

The user needs to display a vector map before using d.path. If no graphics monitor is open, a file `map.png` is generated in the current directory.

The 'from' and 'to' points are entered by mouse into the map displayed in the GRASS monitor, or if the coordinates option is used they can be specified non-interactively. The actions bound to the mouse buttons are described in the terminal window when running the command.

To calculate shortest path non-interactively and save the path to a new vector map, use the v.net.path module.

## EXAMPLES

Interactive shortest path routing on road network (North Carolina sample dataset):

    g.region vector=roadsmajor -p
    d.vect roadsmajor
    d.path roadsmajor coordinates=668646.15,224447.16,668348.83,235894.02

Non-interactive shortest path routing on road network (North Carolina sample dataset):

    d.path -b roadsmajor coordinates=668646.15,224447.16,668348.83,235894.02

## SEE ALSO

v.net.path

## AUTHOR

Radim Blazek, ITC-Irst, Trento, Italy

## SOURCE CODE

Available at: d.path source code (history)

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