Origin-destination matrix (OD matrix)
A table of the trips between places: each row is an origin, each column a destination, and each cell the number of trips between them.
An origin-destination matrix, or OD matrix, records how much movement there is between places. The places are usually zones, such as districts, postcode areas or municipalities. Each row stands for a zone where trips start, each column for a zone where they end, and each cell holds the number of trips, commuters or goods moving from one to the other. In a long table, the same information sits in three columns: origin, destination and value.
| From \ To | Zone A | Zone B | Zone C | Trips starting |
|---|---|---|---|---|
| Zone A | 120 | 340 | 80 | 540 |
| Zone B | 290 | 210 | 150 | 650 |
| Zone C | 60 | 170 | 95 | 325 |
| Trips ending | 470 | 720 | 325 | 1,515 |
Read it row by row: 340 trips a day start in Zone A and end in Zone B. The diagonal, from a zone to itself, counts trips that stay inside one zone. The totals show where trips start and where they end. Zone B is the strongest destination in this example.
| Origin | Destination | Trips |
|---|---|---|
| Zone A | Zone B | 340 |
| Zone B | Zone A | 290 |
| Zone C | Zone B | 170 |
The long form is what most tools expect as input, including GOAT.
OD matrices are the basis of most transport models. They show where demand comes from, which connections carry the most people, and where a new bus line or cycle route would match real travel. The numbers come from travel surveys, commuter statistics, mobile phone data or passenger counts. Each source has its own gaps, so a matrix is usually an estimate.
A similar table, the travel cost matrix, holds travel times or distances between the same places instead of trip numbers. In GOAT, the Origin Destination tool takes an OD matrix and a layer with the zones, and draws each relation as a straight line weighted by its value. The Travel Cost Matrix tool calculates the travel times.