International Date Line, international waters

Oscar van Vlijmen o.van.vlijmen at
Wed Jan 5 12:11:51 UTC 2000

Gwillim Law wrote:

>The International Date Line is not defined by any international standard,
>convention, or treaty.  Mapmakers are free to draw it as they please.
>Reputable mapmakers will simply ensure that every point of land appears on
>the correct side of the IDL, according to the date legally observed there.
>When Kiribati adopted a uniform date in 1995, thereby moving the Phoenix and
>Line Islands to the west side of the IDL (or, if you prefer, moving the IDL
>to the east side of the Phoenix and Line Islands), I suppose that most
>mapmakers redrew the IDL following the boundary of Kiribati.  Even that line
>has a rather arbitrary nature.  The straight-line boundaries between Pacific
>island nations that are shown on many maps are based on an international
>convention, but are not legally binding national borders.

It is possible that this is the most accurate answer given thusfar.

About those straight line borders between the Pacific island nations:

My copy of the "Reference map of oceania" from the University of Hawaii
Press shows only CURVED boundaries.
The latest edition of the Times Atlas, the 10th comprehensive edition,
shows super straight boundary lines.
On the University of Hawaii press map you can find a large spot of "no
man's water" enclosed by the boundaries of Micronesia, Nauru, Gilbert
Islands, Tuvalu, Solomon Islands and Papua New Guinea.
The Times atlas gives the impression that this "no man's water" is just
part of the Solomon Islands, Papua New Guinea and the rest respectively.
Furthermore, the Times atlas gives the impression that Niue, the example
Gwillim Law gave, is part of the Cook Islands including (!) Tokelau and
that a straight border runs immediately left of Niue's island with main
city Alofi.
The University of Hawaii press map by contrast, shows a curved border about
200 kilometers left of Niue, and also separate curved borders around the
Cook Islands and the Tokelau Islands. Tokelau is annotated being a
dependency of New Zealand, the Cook Islands are "free associated" with New
Zealand and Niue has no status.
The US Office of the Geographer and Global Issues of the State Department
lists Niue as a New Zealand dependency, just like Tokelau and Cook

There is probably more on the subject boundaries in:
Law of the Sea, student edition: Chapter 5. Baselines, zones, limits and
I can't find a complete on-line edition and I do no possess a printed copy.
It appears that in 1994 60 nations ratified the UN-sponsored Law of the Sea
Treaty of 1982, which establishes a 12-mile limit for territorial waters,
but many provisions already have been internationally accepted.
These are 12 nautical miles, so 1852 x 12 = 22224 meters.
The Treaty stipulates a 200 nautical mile exclusive economic zone, for
instance for regulating fishing rights and rights for mineral exploitation.
The forerunner of the Law of the sea Treaty 1982, with respect to
territorial boundaries, is the Convention on the Territorial Sea and the
Contiguous Zone of 1958. This one is on-line:

Are we still talking timezones?
Yes, Gwillim Law noted:
>An Anglo-French Conference on Time-Keeping at Sea (June, 1917) agreed that
>legal time on the high seas would be zone time, i.e., the standard time at
>the nearest meridian that is a multiple of fifteen degrees.

When you are out of territorial waters (12 nm) you are in international
waters and you should obey the theoretical timezone, innit?

I made up the following list:

Theoretical timezones:
Take [0;15W), [15;30W),..., [165;180W), [180E;165E),..., [15E;0E)
Times in hours from UT. [ means including, ) means not including.
0-15E   +1
15-30E   +2
30-45E   +3
45-60E   +4
60-75E   +5
75-90E   +6
90-105E   +7
105-120E   +8
120-135E   +9
135-150E   +10
150-165E   +11
165-180E   +12
0-15W   -1
15-30W   -2
30-45W   -3
45-60W   -4
60-75W   -5
75-90W   -6
90-105W   -7
105-120W   -8
120-135W   -9
135-150W   -10
150-165W   -11
165-180W   -12

Is all this information useful or too silly to talk about?

Oscar van Vlijmen

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