Thematic mapper analysis of Nantucket´s nearshore marine environment

While significant advances have been made with respect to the management and planning of the nation´s coastal and nearshore marine environment, landcover information from both the terrestrial and marine portion of the coastal zone has often been difficult to obtain. The fully operational TM sensor onboard Landsat V which was placed in orbit late in 1984 has proved particularly useful for coastal landcover applications. This paper reports on an analysis of Nantucket Island, Massachusetts. The fine resolution (1/4 acre) and the addition of three electromagnetic bands greatly enhances the interpretive capabilities of the Landsat system, especially in the shallow nearshore marine environment. Nantucket Island is the last remnant of a terminal moraine, whose southern and western shores have been eroding since the end of the Pleistocene period. With a projected increase in sea level, these processes are likely to continue, perhaps even increase. Sand, silt and gravel are constantly being transported, trapped, reworked and redeposited by some of the strongest tidal currents in North America. This results in constantly changing banks, reefs, spits and barriers. The fine resolution and the frequency of orbital overpass make scenes from Landsat´s TM sensor a particularly valuable coastal surveillance tool.