Three Brothers, Great Chagos Bank.   Landsat 2 multi-spectral scanner, 1st March 1978.  Left: False colour composite. Right: unsupervised classification, using bands 4, 5, 6 and 'z' which is a depth invariant band. Dark green is land, pale yellow is reef flat. 'Resurgent' is a raised reef between Middle and South Brother, and is dry land although it does not show as green in this treatment.  One of the main passes into the Great Chagos Bank passes south of these islands.  Note the 'atoll' shape of Middle Brother and its lagoon.
(ref: Sheppard, Seaward, Klaus and Topp, 1999. The Chagos Archipelago: An introduction.  In: Sheppard and Seaward (eds) Ecology of The Chagos Archipelago.  Linnean Society Occassional Publications, London. pp 1-22.)
