THE GEOGRAPHY OF TRANSPORT SYSTEMS
Specialization Index
Author: Dr. Claude Comtois
1. The Index
In transport, to find out if a terminal is specialized in the transshipment and/or handling of a particular kind of merchandise or if, inversely, it transfers a wide variety of merchandise, we can calculate a specialization index. For example, the index can be used to know if a port is specialized in the handling of a certain type of product (e.g. containers) or if it handles a wide range of merchandise. As a consequence, such an index is quite versatile and has a variety of applications; it informs geographers on the activities of any type of terminal (port, train and airport). In the case of an airport terminal, one could ask if a given airport deals with only a single type of flights/passengers (local, national, international, etc) or if it welcomes several. The specialization index (SI) is calculated using the following formula:
which is the total of squares of tonnage (or monetary value) of each type of merchandise i (ti) handled at a terminal over the square of the total volume tonnage (or monetary value) of merchandise handled at the terminal.
So, if the specialization index tends toward 1, such a result indicates that the terminal is highly diversified. If, inversely, the index tends toward 0, it means that the terminal's activity is specialized. Thus, the specialization index is called upon to appreciate the degree of specialization/diversification of a port, an airport, a train station or any type of terminal.
2. Example
To show how to calculate the specialization index, we will examine the case of the port of Sept-Iles/Pointe-Noire and the merchandise handled at this port.
| Domestic | International | Domestic and international | ||||
| Merchandise | Loaded | Unloaded | Loaded | Unloaded | Handled | Containerized |
| tons | tons | tons | tons | tons | % | |
| Logs, bolts, and other woods | - | - | 2 | - | 2 | - |
| Wood pulp | - | - | 1 413 | - | 1 413 | - |
| Iron ore | 3 415 905 | - | 16 675 108 | - | 20 091 013 | - |
| Iron, steel, and alloys | 12 129 | - | 5 617 | 94 | 17 840 | 0.2 |
| Aluminum ore and basic products | - | - | 180 420 | 413 861 | 594 281 | - |
| Other ores & base metal products | 35 243 | - | 61 060 | 630 | 96 933 | 0.2 |
| Coal | - | - | 156 550 | 153 190 | 309 740 | - |
| Limestone | - | 143 045 | - | 186 869 | 329 914 | - |
| Salt | - | 10 993 | - | - | 10 993 | - |
| Auth. Non-metallic mineral products. | 2 060 | 204 496 | 1 494 | 165 918 | 373 958 | 0.8 |
| Miscellaneous chemicals | - | 3 559 | 28 | 3 037 | 6 624 | 0.4 |
| Gasoline | 2 539 | 43 890 | - | - | 46 429 | - |
| Fuel oil | - | 280 038 | - | 17 135 | 297 173 | - |
| Coke of petroleum and coal | - | 60 766 | 54 863 | 287 987 | 403 617 | - |
| Cement and related products | - | - | - | 127 | 127 | - |
| Machinery/equp & misc. cargo | 2 629 | 19 | 89 | 1 136 | 3 873 | 0.4 |
| Total | 3 470 505 | 746 796 | 17 136 645 | 1 229 985 | 22 583 930 | - |
Source: Statistics Canada, Cat. No. 54-205.
Thus, by using the above equation, we find a specialization index of 0.79. Obtaining an index drawing close to 1, we can conclude that the port of Sept-Iles/Pointe-Noire is highly specialized. By looking at the table, we see immediately that the handling of iron ore is the port's specialty. It can be noted that the same calculation can be performed using the loaded and unloaded products or with the domestic and international traffic.
