A Gradual Approach for Multimodel Journey Planning: A Case Study in Izmir, Turkey

Algorithm 2

Finding routes containing two transfers.

Inputs: origin, origin line ,  , ,

for each node n in Graph:

-n.dist  ≔ infinity;

-n.trCnt  ≔ 0;   //  Transfer Count

-n.previous  ≔ undefined;

origin.dist  ≔ 0;

Q  ≔ Priority queue according to distance;

enqueue origin into Q;

while Q.isEmpty != true:

-u  ≔ node with min distance in Q;

-remove u from Q;

-for each outbound edge e of node u:

--v  ≔ node reachable from u with edge e;

--e.weight  ≔ infinity;

--if e.Line  :

---if u.previous != null: prev_e  ≔  edge used for reaching to u;

----if e is a line:

-----if ((u.trCnt = 2 and e.Line = prev_e.Line) or

          (u.trCnt = 1 and e.Line != prev_e.Line and e.Line  ∈  ) or

          (u.trCnt = 1 and e.Line = prev_e.Line) or

          (u.trCnt = 0 and e.Line != prev_e.Line and e.Line  ∈  ) or

          (u.trCnt = 0 and e.Line = prev_e.Line)): e.weigth  ≔  ;

----else  //  e is a foot-edge

-----if ((u.trCnt = 0 and prev_e is a line) or

-----  (u.trCnt = 1 and prev_e is a line)): e.weigth  ≔  ;

-----else e.weigth  ≔ infinity;

---else  //  u.previous = null:

----if e.Line is : e.weigth  ≔  ;

-for each outbound edge e of node u:

--v  ≔ node reachable from u with edge e;

--prev_e  ≔ edge used for reaching to u;

--dist_v  ≔  u.dist + e.weigth;

--if dist_v < v.dist:

---dequeue v from Q with key v.dist;

---v.dist  ≔  dist_v;

---v.previous  ≔  u;

---v.trCnt  ≔  u.trCnt;

---if e.Line != prev_e.Line: v.trCnt  ≔  u.trCnt + 1;

---enqueue v into Q with key dist_v;

S  ≔ empty sequence;

u  ≔ target;

while u.previous is not null:

-insert u into S;

-u  ≔  u.previous;