Edgartown, MA Coastal Erosion Rate
What USGS measures 3.4 miles east of Edgartown, MA
Good news, and an honest one: USGS's data can't distinguish this stretch, 3.4 miles east of Edgartown, MA, from a flat trend. Whatever small movement it measured here is statistical noise, not a reliable direction, so none is claimed.
What "Edgartown" means on this page
USGS surveys the coast in transects spaced a few hundred feet apart; this page groups the nearest ones into a single ~3.5-mile reading for the stretch closest to Edgartown, MA, rather than showing one arbitrary line. Segment center: 41.40, -70.46. Survey years: 2007-2009, method LRR, from USGS's New England / Mid-Atlantic shoreline-change assessment. That's how current the data is here, real, but not a live feed, since a shoreline survey is a major undertaking, not an annual check-in.
Where this fits nationally
This reading comes from 101 individual transects averaged together, 71% of which measured erosion rather than growth. USGS's confidence interval here is ±0.29 ft/yr. The unadjusted figure here, -0.2 ft/yr, would place it 504 of 1211 if ranked directly - but an unreliable rank isn't a useful one, which is exactly why "no significant trend" is the headline instead. Source: USGS Open-File Report 2010-1119. For scale: Coronado, CA, 2613 miles away, ranks 1125 of 1211 nationally for growth, 1.22 ft/yr. 2.8 miles up the coast, Edgartown, MA shows the same lack of a significant trend.
Not this whole stretch, just Edgartown itself: the Coastal Change Hazards Portal is USGS's own live version of this data.