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    Re: Visit beautiful Sandy Island...
    From: Frank Reed
    Date: 2012 Nov 23, 17:36 -0800

    The island in Google Maps is about 20 miles long north-to-south by a few miles wide. That's fairly big for bad map data. I've found a couple of interesting clues. First, if you look at it in Google Maps, it's clearly a rather poorly defined polygon consisting of 20 to 25 points. That's low resolution. Second, it's also in Bing maps, but only at some scales. If you go to bing.com/maps and look at the area west of New Caledonia at a scale such that that the scale bar in the corner shows "100 miles" and "200 km", you can see the phantom island right where it is in Google Maps. But if you zoom in, it grows in size during the animation and then fades out before your eyes. These two clues suggest (to me, based on my own experience with this sort of data) that the island was generated by a low resolution vector shoreline probably within the past twenty years.

    Here's a standard vector shoreline generator that offers up some of the low resolution datasets:
    http://www.ngdc.noaa.gov/mgg/shorelines/shorelines.html
    And sure enough, if you set the bounding rectangle right, you will see that polygonal island. How it got in there may not be possible to figure out at this "late date" since the dataset was probably created at a very early point in the digitization epoch (1980s possibly!). I tried a few simple possibilities, like mirrored duplication from another lat, lon. If you switch the latitude from South to North and the longitude from East to West, you end up quite close to Hawaii, but there's no "twin" there that could explain it...

    Still another possibility. We have found Captain Nemo! As Alex Eremenko asked in his first post for NavList in September of 2004: "Do the following islands exist (or DID they exist in XIX century?): Tabor (a.k.a. Maria Teresa) and Ernest Leguve Reef?" and "One conjecture is that the islands existed in XIX century but
    then disappeared as a result of the motion of the ocean floor... Or did Jules Verne invent them, and Russian map makers placed them according to Jules Verne? :-)"

    -FER


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