1v.net.timetable(1) GRASS GIS User's Manual v.net.timetable(1)
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6 v.net.timetable - Finds shortest path using timetables.
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9 vector, network, shortest path
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12 v.net.timetable
13 v.net.timetable --help
14 v.net.timetable input=name [layer=string] output=name
15 [arc_layer=string] [node_layer=string] [arc_column=string]
16 [arc_backward_column=string] [node_column=string]
17 [walk_layer=string] route_id=name stop_time=name to_stop=name
18 walk_length=name [--overwrite] [--help] [--verbose] [--quiet]
19 [--ui]
20 Flags:
22 --overwrite
23 Allow output files to overwrite existing files
24 --help
26 Print usage summary
27 --verbose
29 Verbose module output
30 --quiet
32 Quiet module output
33 --ui
35 Force launching GUI dialog
36 Parameters:
38 input=name [required]
39 Name of input vector map
40 Or data source for direct OGR access
41 layer=string
43 Layer number or name
44 Vector features can have category values in different layers. This
45 number determines which layer to use. When used with direct OGR
46 access this is the layer name.
47 Default: 1
48 output=name [required]
50 Name for output vector map
51 arc_layer=string
53 Arc layer
54 Vector features can have category values in different layers. This
55 number determines which layer to use. When used with direct OGR
56 access this is the layer name.
57 Default: 1
58 node_layer=string
60 Node layer
61 Vector features can have category values in different layers. This
62 number determines which layer to use. When used with direct OGR
63 access this is the layer name.
64 Default: 2
65 arc_column=string
67 Arc forward/both direction(s) cost column (number)
68 arc_backward_column=string
70 Arc backward direction cost column (number)
71 node_column=string
73 Node cost column (number)
74 walk_layer=string
76 Layer number or name with walking connections or -1
77 A single vector map can be connected to multiple database tables.
78 This number determines which table to use. When used with direct
79 OGR access this is the layer name.
80 Default: -1
81 route_id=name [required]
83 Name of column with route ids
84 Default: route_id
85 stop_time=name [required]
87 Name of column with stop timestamps
88 Default: stop_time
89 to_stop=name [required]
91 Name of column with stop ids
92 Default: to_stop
93 walk_length=name [required]
95 Name of column with walk lengths
96 Default: length
97
99 v.net.timetable finds the shortest path between two points using
100 timetables. v.net.timetable reads input, one query per line, from the
101 standard input and writes output to the standard output as well as to
102 the output map and to tables linked to layers 1 and 2. Each line of
103 input must follow one of the following formats:
104 PATH_ID FROM_X FROM_Y TO_X TO_Y START_TIME MIN_CHANGE MAX_CHANGES WALK_CHANGE
105 PATH_ID FROM_STOP TO_STOP START_TIME MIN_CHANGE MAX_CHANGES WALK_CHANGE
106 where PATH_ID is the identificator of a query that is used in the out‐
107 put map to differentiate between queries. Search begins at START_TIME.
108 MIN_CHANGE gives the minimum number of time (inclusively) for a change
109 from one route to another. MAX_CHANGES denotes the maximum number of
110 changes allowed or -1 if infinity. WALK_CHANGE is 1 or 0 depending
111 whether walking from a stop to another stop is considered a change or
112 not. Finally, the path is found from FROM_STOP to TO_STOP in latter
113 case and from the stop closest to (FROM_X, FROM_Y) coordinates to the
114 stop closest to (TO_X, TO_Y) coordinates in former case.
115 For each input query, module outputs a description of the shortest path
116 to the standard output. For example, using the tables given below, for
117 the following input:
118 47 130 300 0 1 5 0
119 the following output is produced:
120 Route 15, from 130 leaving at 15 arriving to 250 at 22
121 Walk from 250 leaving at 22 arriving to 300 at 24
122 Moreover, the module writes the path to the output map and stores all
123 the information necessary to reconstruct the path to the tables. Table
124 corresponding to stops/points is linked to layer 1 and looks, after the
125 query, as follows:
126 cat|path_id|stop_id|index|arr_time|dep_time
127 1|47|130|1|0|15
128 2|47|250|2|22|22
129 3|47|300|3|24|24
130 where CAT is the category of a point in the map, PATH_ID is the path
131 identificator, STOP_ID is the identificator of the stop as used in the
132 input map, INDEX is the index of the stop on the path (i.e, index=1 is
133 the first stop visited, ...) and ARR_TIME and DEP_TIME denote the
134 arrival time and departure time respectively. Arrival time for the
135 first stop on the path is always equal to START_TIME and departure time
136 for the last stop is always equal to the arrival time.
137 The table linked to the second layer corresponds to subroutes taken
138 between stops. The following table is obtainedd for the above query:
139 cat|path_id|from_id|to_id|route_id|index|from_time|to_time
140 1|47|130|250|15|1|15|22
141 2|47|250|300|-1|2|22|24
142 where CAT is the category of lines of subroute between stops FROM_ID to
143 TO_ID, ROUTE_ID is the identificator of the route taken or -1 if walk‐
144 ing, INDEX and PATH_ID are as above and FROM_TIME and TO_TIME denote
145 the times between which the route is taken.
146 The output map contains the points on the positions of used stops. If a
147 subroute is taken between two stops then a line segment is added
148 between two corresponding points. Finally, instead of straight line
149 segment, the actual paths of routes can be given in paths layer. If
150 this parameter is used then each line in the input map must contain
151 identificators as category numbers of all routes passing through the
152 line. The module then finds the path between two stops and writes this
153 path instead. In case of walking from one stop to another, straight
154 line between the stops is used.
155
157 Timetables are stored in a table linked to the given layer of the input
158 map. Timetable consists of routes and each route is just a sequence of
159 stops with specified arrival times. If two sequences of stops differ
160 only in times then they still correspond to two routes. For example, if
161 there is a bus line that leaves every 20 minutes and follow exactly the
162 same path every time then there still needs to be a separate route for
163 every time. For each stop (given by the category number of the point)
164 the table storing information about the routes must contain the list of
165 all routes stopping at the stop(given by route identificators) together
166 with arrival times. That is, the table must contain three columns: stop
167 - which is the key of the table, route_id and stop_time where each
168 triple corresponds to a route arriving to a stop and a certain time.
169 For example, a valid table might look as follows:
170 cat|route_id|stop_time
171 100|5|0
172 130|5|10
173 150|5|20
174 250|5|30
175 300|5|40
176 260|15|5
177 130|15|15
178 250|15|22
179 150|35|17
180 250|35|27
181 300|35|37
182 100|35|50
183 Note that stop_time is an integer and so you can use any units and
184 offest to specify arrival times.
185 Also, walking connections between stops can be given by a table linked
186 to walking layer of the input map. If this parameter is -1 then walking
187 between stops is not allowed. The table must contain three columns:
188 stop - which is the key of the table, to_stop and length. A record in
189 the table says that it takes length
190 units of time to walk from stop to to_stop. The following is a valid
191 table:
192 cat|length|to_stop
193 250|2|300
194 Beware that this only means that it is possible to walk from stop 250
195 to stop 300 but not the other way round.
196
198 To find a path from stop with identificator 130 to stop with category
199 300, starting at time 0, with one time unit for change, maximum of 5
200 changes and with walking not considered a change of route, we use the
201 following command:
202 echo "47 130 300 0 1 5 0" | v.net.timetable \
203 input=buses output=path layer=5 walking=6 path=7
204 If, on the other hand, we know the coordinates of the places then the
205 following command might be used:
206 echo "47 10.31 54.31 90.21 28.21 0 1 5 0" | v.net.timetable \
207 input=buses output=path layer=5 walking=6 path=7
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210 v.net, v.net.path, v.net.distance
211
213 Daniel Bundala, Google Summer of Code 2009, Student
214 Wolf Bergenheim, Mentor
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217 Available at: v.net.timetable source code (history)
218 Main index | Vector index | Topics index | Keywords index | Graphical
220 index | Full index
221 © 2003-2020 GRASS Development Team, GRASS GIS 7.8.5 Reference Manual
223GRASS 7.8.5 v.net.timetable(1)