Why was Sandy Island on maps for over a century?

Sandy Island was a phantom island charted for over a century in the Coral Sea near New Caledonia before being proven not to exist. Despite being removed from French hydrographic charts in 1974, it remained on many global maps and digital databases until an Australian research ship "undiscovered" it in November 2012. Phantom islands like this typically originate from early navigational errors, mistaken observations, or unverified reports.

What we know

Sandy Island was charted for over a century near New Caledonia in the eastern Coral Sea between the Chesterfield Islands and Nereus Reef, and was included on charts from the late 19th century onwards. [1, 2]
The island was removed from French hydrographic charts in 1974, yet persisted on other maps and datasets. [2]
In November 2012, the Australian research ship R/V Southern Surveyor passed through the area and proved the island did not exist, leading to its rapid removal from datasets like Google Maps and National Geographic. [2]
Phantom islands are purported islands appearing on maps that are later found not to exist, commonly resulting from early navigational errors, mistaken observations, unverified misinformation, or deliberate fabrication. [3]

Where to go next

Sources

[1]Sandy Island (Wikidata Q80326) · CC0 1.0
[2]Sandy Island, New Caledonia · CC BY-SA 4.0
[3]Phantom island · CC BY-SA 4.0
[4]Chesterfield Islands · CC BY-SA 4.0
[5]Canton Island · CC BY-SA 4.0