cs2cs +proj=latlong +ellps=intl +towgs84=306,304,-318 +to +proj=latlong +datum=WGS84
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84d59'49.121"W  10d0'10.74"S 0.000
-77 -10
76d59'47.965"W  10d0'10.464"S 0.000
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68d59'47.043"W  10d0'10.163"S 0.000
-61 -10
60d59'46.373"W  10d0'9.843"S 0.000
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84d59'49.265"W  3d30'10.521"S 0.000
-77 -3.5
76d59'48.124"W  3d30'10.424"S 0.000
-69 -3.5
68d59'47.215"W  3d30'10.318"S 0.000
-61 -3.5
60d59'46.554"W  3d30'10.206"S 0.000
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84d59'49.27"W   2d59'49.822"N 0.000
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76d59'48.13"W   2d59'49.739"N 0.000
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68d59'47.221"W  2d59'49.648"N 0.000
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60d59'46.561"W  2d59'49.552"N 0.000
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84d59'49.137"W  9d29'50.31"N 0.000
-77 9.5
76d59'47.983"W  9d29'50.048"N 0.000
-69 9.5
68d59'47.062"W  9d29'49.762"N 0.000
-61 9.5
60d59'46.394"W  9d29'49.458"N 0.000
-85 16
84d59'48.856"W  15d59'50.961"N 0.000
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76d59'47.672"W  15d59'50.523"N 0.000
-69 16
68d59'46.728"W  15d59'50.046"N 0.000
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60d59'46.042"W  15d59'49.539"N 0.000