Service_area

network-functions service_area

syntax

  • service_area(F1, F2, dijkstra/traceback)

definition

service_area(F1, F2, dijkstra/traceback) calculates service areas for nodes in the network.

A service area is defined as the relation to the nearest destination node for each node in the node set. The results are based on the results of impedance-obsolete-dijkstra calculations.

The service_area function requests three argument:

  • F1: relation to the first node of a linkset;
  • F2: relation to the last node of a linkset;
  • dijkstra/traceback: the traceback item, a generated subitem by the dijkstra function.

description

The function results in a relation to the nodes in the nodeset. Use the lookup function to relate these numbers to the origin locations (see example).

applies to

attribute F1, F2 and dijkstra/traceback with uint32 value-type

conditions

The domain-unit of attributes F1 and F2 must match.

example

attribute<meter>       dist           (nodeset) := dijkstra(dist, F1, F2, nr_DestNode);
attribute<destination> servicearea_ns (nodeset) := 
   rlookup(
      service_area(
          F1 
         ,F2
         ,dist/TraceBack
       )
       , nr_DestNode
   ); 
attribute<destination> servicearea (origin) := servicearea_ns[nr_OrgNode];
F1 F2
8 7
1 4
16 15
2 3
5 4
6 7
9 10
12 11
14 15
18 20
19 17
3 0
4 11
7 1
10 3
11 13
13 17
15 10
20 21
17 20

domain linkset, nr of rows = 19

nr_DestNode
14
6
2
19

domain destination, nr of rows = 5

servicearea
0
1
2
3
1

domain origin, nr of rows = 5