v.net.timetable
Finds shortest path using timetables.
v.net.timetable input=name [layer=string] output=name [arc_layer=string] [node_layer=string] [arc_column=string] [arc_backward_column=string] [node_column=string] [walk_layer=string] route_id=name stop_time=name to_stop=name walk_length=name [--overwrite] [--verbose] [--quiet] [--qq] [--ui]
Example:
v.net.timetable input=name output=name route_id=route_id stop_time=stop_time to_stop=to_stop walk_length=length
grass.script.run_command("v.net.timetable", input, layer="1", output, arc_layer="1", node_layer="2", arc_column=None, arc_backward_column=None, node_column=None, walk_layer="-1", route_id="route_id", stop_time="stop_time", to_stop="to_stop", walk_length="length", overwrite=False, verbose=False, quiet=False, superquiet=False)
Example:
gs.run_command("v.net.timetable", input="name", output="name", route_id="route_id", stop_time="stop_time", to_stop="to_stop", walk_length="length")
Parameters
input=name [required]
Name of input vector map
Or data source for direct OGR access
layer=string
Layer number or name
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
output=name [required]
Name for output vector map
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 (number)
walk_layer=string
Layer number or name with walking connections or -1
A single vector map can be connected to multiple database tables. This number determines which table to use. When used with direct OGR access this is the layer name.
Default: -1
route_id=name [required]
Name of column with route ids
Default: route_id
stop_time=name [required]
Name of column with stop timestamps
Default: stop_time
to_stop=name [required]
Name of column with stop ids
Default: to_stop
walk_length=name [required]
Name of column with walk lengths
Default: length
--overwrite
Allow output files to overwrite existing files
--help
Print usage summary
--verbose
Verbose module output
--quiet
Quiet module output
--qq
Very quiet module output
--ui
Force launching GUI dialog
input : str, required
Name of input vector map
Or data source for direct OGR access
Used as: input, vector, name
layer : str, optional
Layer number or name
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.
Used as: input, layer
Default: 1
output : str, required
Name for output vector map
Used as: output, vector, name
arc_layer : str, optional
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.
Used as: input, layer
Default: 1
node_layer : str, optional
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.
Used as: input, layer
Default: 2
arc_column : str, optional
Arc forward/both direction(s) cost column (number)
arc_backward_column : str, optional
Arc backward direction cost column (number)
node_column : str, optional
Node cost column (number)
walk_layer : str, optional
Layer number or name with walking connections or -1
A single vector map can be connected to multiple database tables. This number determines which table to use. When used with direct OGR access this is the layer name.
Used as: input, layer
Default: -1
route_id : str, required
Name of column with route ids
Used as: input, dbcolumn, name
Default: route_id
stop_time : str, required
Name of column with stop timestamps
Used as: input, dbcolumn, name
Default: stop_time
to_stop : str, required
Name of column with stop ids
Used as: input, dbcolumn, name
Default: to_stop
walk_length : str, required
Name of column with walk lengths
Used as: input, dbcolumn, name
Default: length
overwrite: bool, optional
Allow output files to overwrite existing files
Default: False
verbose: bool, optional
Verbose module output
Default: False
quiet: bool, optional
Quiet module output
Default: False
superquiet: bool, optional
Very quiet module output
Default: False
DESCRIPTION
v.net.timetable finds the shortest path between two points using timetables. v.net.timetable reads input, one query per line, from the standard input and writes output to the standard output as well as to the output map and to tables linked to layers 1 and 2. Each line of input must follow one of the following formats:
PATH_ID FROM_X FROM_Y TO_X TO_Y START_TIME MIN_CHANGE MAX_CHANGES WALK_CHANGE
PATH_ID FROM_STOP TO_STOP START_TIME MIN_CHANGE MAX_CHANGES WALK_CHANGE
where PATH_ID is the identifier of a query that is used in the output
map to differentiate between queries. Search begins at START_TIME.
MIN_CHANGE gives the minimum number of time (inclusively) for a change
from one route to another. MAX_CHANGES denotes the maximum number of
changes allowed or -1 if infinity. WALK_CHANGE is 1 or 0 depending
whether walking from a stop to another stop is considered a change or
not. Finally, the path is found from FROM_STOP to TO_STOP in latter case
and from the stop closest to (FROM_X, FROM_Y) coordinates to the stop
closest to (TO_X, TO_Y) coordinates in former case.
For each input query, module outputs a description of the shortest path
to the standard output. For example, using the tables given below, for
the following input:
47 130 300 0 1 5 0
the following output is produced:
Route 15, from 130 leaving at 15 arriving to 250 at 22
Walk from 250 leaving at 22 arriving to 300 at 24
Moreover, the module writes the path to the output map and stores all the information necessary to reconstruct the path to the tables. Table corresponding to stops/points is linked to layer 1 and looks, after the query, as follows:
cat|path_id|stop_id|index|arr_time|dep_time
1|47|130|1|0|15
2|47|250|2|22|22
3|47|300|3|24|24
where CAT is the category of a point in the map, PATH_ID is the path
identifier, STOP_ID is the identifier of the stop as used in the input
map, INDEX is the index of the stop on the path (i.e, index=1 is the
first stop visited, ...) and ARR_TIME and DEP_TIME denote the arrival
time and departure time respectively. Arrival time for the first stop on
the path is always equal to START_TIME and departure time for the last
stop is always equal to the arrival time.
The table linked to the second layer corresponds to subroutes taken
between stops. The following table is obtained for the above query:
cat|path_id|from_id|to_id|route_id|index|from_time|to_time
1|47|130|250|15|1|15|22
2|47|250|300|-1|2|22|24
where CAT is the category of lines of subroute between stops FROM_ID to
TO_ID, ROUTE_ID is the identifier of the route taken or -1 if walking,
INDEX and PATH_ID are as above and FROM_TIME and TO_TIME denote the
times between which the route is taken.
The output map contains the points on the positions of used stops.
If a subroute is taken between two stops then a line segment is added
between two corresponding points. Finally, instead of straight line
segment, the actual paths of routes can be given in paths layer. If
this parameter is used then each line in the input map must contain
identifiers as category numbers of all routes passing through the line.
The module then finds the path between two stops and writes this path
instead. In case of walking from one stop to another, straight line
between the stops is used.
NOTES
Timetables are stored in a table linked to the given layer of the input map. Timetable consists of routes and each route is just a sequence of stops with specified arrival times. If two sequences of stops differ only in times then they still correspond to two routes. For example, if there is a bus line that leaves every 20 minutes and follow exactly the same path every time then there still needs to be a separate route for every time. For each stop (given by the category number of the point) the table storing information about the routes must contain the list of all routes stopping at the stop(given by route identifiers) together with arrival times. That is, the table must contain three columns: stop - which is the key of the table, route_id and stop_time where each triple corresponds to a route arriving to a stop and a certain time. For example, a valid table might look as follows:
cat|route_id|stop_time
100|5|0
130|5|10
150|5|20
250|5|30
300|5|40
260|15|5
130|15|15
250|15|22
150|35|17
250|35|27
300|35|37
100|35|50
Note that stop_time is an integer and so you can use any units and
offset to specify arrival times.
Also, walking connections between stops can be given by a table linked
to walking layer of the input map. If this parameter is -1 then
walking between stops is not allowed. The table must contain three
columns: stop - which is the key of the table, to_stop and
length. A record in the table says that it takes length units of
time to walk from stop to to_stop. The following is a valid table:
cat|length|to_stop
250|2|300
Beware that this only means that it is possible to walk from stop 250 to stop 300 but not the other way round.
EXAMPLES
To find a path from stop with identifier 130 to stop with category 300, starting at time 0, with one time unit for change, maximum of 5 changes and with walking not considered a change of route, we use the following command:
echo "47 130 300 0 1 5 0" | v.net.timetable \
input=buses output=path layer=5 walking=6 path=7
If, on the other hand, we know the coordinates of the places then the following command might be used:
echo "47 10.31 54.31 90.21 28.21 0 1 5 0" | v.net.timetable \
input=buses output=path layer=5 walking=6 path=7
SEE ALSO
v.net, v.net.path, v.net.distance
AUTHORS
Daniel Bundala, Google Summer of Code 2009, Student
Wolf Bergenheim, Mentor
SOURCE CODE
Available at: v.net.timetable source code
(history)
Latest change: Friday Feb 07 19:16:09 2025 in commit a82a39f