ElizabethIslands_transects_rates_STepr.shp - Digital Shoreline Analysis System version 4.3 transects and short-term (1970-2009) end point shoreline change statistics for the Elizabeth Islands coastal region from Nonamesset Island southwest of Woods Hole to Cuttyhunk Island north of Martha's Vineyar

Due to continued coastal population growth and increased threats of erosion, current data on trends and rates of shoreline movement are required to inform shoreline and floodplain management. The Massachusetts Office of Coastal Zone Management launched the Shoreline Change Project in 1989 to identify erosion-prone areas of the coast. In 2001, a 1994 shoreline was added to calculate both long- and short-term shoreline change rates at 40-meter intervals along ocean-facing sections of the Massachusetts coast.

The Coastal and Marine Geology Program of the U.S. Geological Survey (USGS) in cooperation with the Massachusetts Office of Coastal Zone Management, has compiled reliable historical shoreline data along open-facing sections of the Massachusetts coast under the Massachusetts Shoreline Change Mapping and Analysis Project 2013 Update. Two oceanfront shorelines for Massachusetts (approximately 1,800 km) were (1) delineated using 2008/09 color aerial orthoimagery, and (2) extracted from topographic LIDAR datasets (2007) obtained from NOAA's Ocean Service, Coastal Services Center. The new shorelines were integrated with existing Massachusetts Office of Coastal Zone Management and USGS historical shoreline data in order to compute long- and short-term rates using the latest version of the Digital Shoreline Analysis System (DSAS).

鉴于沿海人口持续增长，海岸侵蚀威胁日益加剧，当前亟需海岸线变化趋势与速率的相关数据，以支撑海岸线及洪泛区的管理工作。马萨诸塞州海岸带管理办公室（Massachusetts Office of Coastal Zone Management）于1989年启动海岸线变化项目（Shoreline Change Project），旨在识别海岸易侵蚀区域。2001年，研究人员新增1994年的海岸线数据，以沿马萨诸塞州沿海面向大洋的岸段，按40米间隔计算海岸线的长期与短期变化速率。

美国地质调查局（U.S. Geological Survey, USGS）海岸与海洋地质项目联合马萨诸塞州海岸带管理办公室，依托《马萨诸塞州海岸线变化制图与分析项目2013年更新版》，完成了马萨诸塞州开阔岸段可靠历史海岸线数据的汇编工作。本次共生成两条马萨诸塞州沿海岸线（总长约1800千米）：其一通过2008/2009年彩色航空正射影像（color aerial orthoimagery）勾勒得到，其二则从美国国家海洋和大气管理局（National Oceanic and Atmospheric Administration, NOAA）海洋服务局海岸服务中心获取的2007年地形激光雷达（LIDAR）数据集（topographic LIDAR datasets）中提取。研究人员将新生成的海岸线与马萨诸塞州海岸带管理办公室及USGS已有的历史海岸线数据进行整合，借助最新版数字海岸线分析系统（Digital Shoreline Analysis System, DSAS）计算海岸线的长期与短期变化速率。