Geographia Polonica (2013) vol. 86, iss. 2
When to stop collecting data on ship movements?
Data available from international shipping consultants becomes less reliable in the 60,000–15,000 dwt range and thisis where specialized regional consultancies step in. A rational approach to dealing with the problem is sought in threeways. First, the increase in cumulative worldwide vessel count is compared with the corresponding cargo value as smallersize classes are added. At 25,000 dwt the vessel count equals the cargo value, suggesting a cut-off point. Second, cargovalues by port are scaled with corresponding port visits (score) and then segments are merged stepwise from the largestto the smallest. Now the expected inflection point fails to emerge. Third, the above score is mapped in a roster of 30 regions. A contrast emerges between large vessel – long distance and small vessel – short distance zones, which explainsthe existence of regional consultancies.
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