Information Technology Reference
In-Depth Information
Tabl e 8. 1
Overview of the maritime database
1996 2006
No. ports 975 1,240
No. countries 157 173
No. vessels movements 176,439 390,740
No. vessels 1,759 3,973
No. operators 497 720
Total slot capacity (TEUs) 3,352,849 9,590,309
Total deadweight capacity (DWTs) 50,644,151 130,742,023
Share world fleet (% containerships) 91.52 98.33
Share world fleet (% TEUs) 92.15 97.91
Share world fleet (% DWTs) 6.23 12.54
Source: calculated by the author based on LMIU and UNCTAD
together with the fleet capacity of the companies by vessel. Although such infor-
mation would permit the building of a world graph of inter-port linkages and has
the advantage of a cheaper cost compared to other sources, it necessitates large
amounts of manual data encoding. Another problem is the lack of coverage on local
and regional services and the probable mismatch with effective ports of call.
Two other sources provide numeric information on effective vessel movements.
First, the French ship broker Barry Rogliano Salles through its branch company
AXS Marine maintains the Alphaliner database on container vessel movements.
Second, the source used in this chapter is derived from Lloyd's Marine Intelligence
Unit (LMIU), a service of Lloyd's, the world leader in maritime insurance and
shipping information based in London. This data source is selected because of its
wide coverage of the world fleet (98 % TEUs
4
in 2006), as seen in Table
8.1
.The
data also include ship operators' names and daily ports of call (previous, current,
and next), thus allowing for many measurements by link and by port.
A fundamental reflection is necessary about the way vessel movements should
be computed to address issues of port performance and port regions. Several aspects
deserve careful attention:
Weight and frequency of linkages
: Many vessel movements of different capacities
pass through the same links within a given period of time. Therefore, edges can
be weighted according to the total traffic (the sum of all vessel capacities), the
number of vessels, the number of calls, or by ratios such as the average vessel
capacity, the weekly average number of calls, etc. In this study, we retain the total
traffic realized by the overall circulation of vessels within 1 year in 1996 and
2006. The same applies to vertices (ports) that can be weighted and compared
based on their total capacity circulated.
4
Twenty-Foot Equivalent Unit (TEU): a normalized measure of container traffic and vessel
capacity referring to the number of 20-foot container boxes. Vessel capacities can also be measured
in deadweight tonnage (DWT) or “commercial capacity”.
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