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Sandy Island, New Caledonia
Sandy Island (sometimes labelled in (フランス語:Île de Sable, and in Spanish: Isla Arenosa)) is a non-existent island that was charted for over a century as being located near the French territory of New Caledonia between the Chesterfield Islands and Nereus Reef in the eastern Coral Sea.〔 The island was included on many maps and nautical charts from as early as the late 19th century, and gained wide media and public attention in November 2012 when the R/V ''Southern Surveyor'', an Australian surveyor ship, passed through the area and "undiscovered" it. The island was quickly removed from many maps and data sets, including those of the National Geographic Society and Google Maps.〔
== History ==
In 1774, Captain James Cook charted a "Sandy Island" 420 kilometers due east at approximately 19° S latitude and at just less than 164 degrees of longitude (rather than just less than 160 degrees of longitude for the phantom "Sandy Island" on charts and maps after 1876). The associated map was published in 1776.〔See David Rumsey Historical Map Collection.〕〔French maps from 1826 and 1875 show "Ile de Sable(s)" at the location of Cook's "Sandy Island".〕 This "Sandy Island", though at the same latitude, is four degrees of longitude further east and may or may not have been associated with the "standard" location after 1876.
The whaling ship ''Velocity'' reported the island in the year 1876, as was noted on various late 1800's maps, including an 1881 German map and 1895 British Admiralty chart.〔 After returning from a voyage in the Pacific, the ''Velocity's'' master reported two unusual features. The first was a series of "heavy breakers", the second some "Sandy Islets", or Sandy Island. Both then appeared in an Australian maritime directory for 1879. It noted the islets extended north and south "along the meridian 159° 57' E" and "between lat 19° 7' S and 19° 20' S". Until 1876-79 (and in reality), the nearest charted land or reef was the Chesterfield Islands 100 km westwards on the Bellona Plateau. At the time when the chart was created, it was standard practice for all potential navigation hazards to be listed on such charts as a precaution.
Hydrographic charts later placed the internationally recognized abbreviation "ED" ("existence doubtful") next to Sandy Island, in recognition of subsequent failures to spot the reported island at the expected location. Seafloor mapping in the area by the Australian Hydrographic Service (AHS) determined a minimum depth for the immediate area around and over the island ranging from 1488 to 2353 meters below sea level. Due to a lack of appearance of an island or depths indicating a shallow reef, Sandy Island was removed from the official French hydrographic charts by the French Hydrographic Service in 1979 after a flying recognition campaign and by AHS in 1985. The information about the status of the phantom island was passed on to other national hydrographic services around the world, but Sandy Island remained in global coastline and bathymetry compilations used by the scientific community and was still there when the R/V ''Southern Surveyor'' sailed toward the Coral Sea in October 2012. The erroneously reported island persisted because it was included in the World Vector Shoreline Database (WVS), a data set originally developed by the U.S. National Imagery and Mapping Agency (now the National Geospatial‐Intelligence Agency, NGA) during the conversion from physical charts to digital formats, and now used as a standard global coastline data set. Inconsistencies in this data set exist in some of the least explored parts of Earth, due to human digitizing errors and errors in original maps from which the digitizing took place. One of the most commonly used derived products of WVS is the Global Self-consistent, Hierarchical, High-resolution Shoreline Geography Database (GSHHG), which is ported with Generic Mapping Tools (GMT) software. Although it is now an independent data set, an error in the original WVS data would have been present in this data set.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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