Does anybody know the exact geographical coordinates of the international date line?

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. 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. The date is governed by the IDL; therefore, even on the high seas, there may be some places as late as fourteen hours later than UTC. And, since the IDL is not an international standard, there are some places on the high seas where the correct date is ambiguous. This information is the best I could find when I was studying the question a few years ago. If any of the readers of this list have anything more authoritative, I would welcome corrections. Gwillim Law