Nantucket_transects_rates_STlr.shp - Digital Shoreline Analysis System version 4.3 transects and short-term (1970-2009) linear regression shoreline change statistics within the Nantucket coastal region including the Nantucket Sound- and Atlantic Ocean- facing coasts of Nantucket, Muskeget and Tuck

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，当前亟需获取海岸线变迁趋势与速率的相关数据，以支撑海岸线及洪泛区的管理决策。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，研究团队新增1994年海岸线数据，沿马萨诸塞州面向海洋的海岸段以40米为间隔，计算海岸线长期与短期变迁速率。

美国地质调查局（U.S. Geological Survey, USGS）海岸与海洋地质项目组与马萨诸塞州海岸带管理办公室合作，依托《马萨诸塞州海岸线变化制图与分析项目2013年更新版》，完成了马萨诸塞州面向开阔海域海岸段的可靠历史海岸线数据整编工作。本次研究共获取两条总长约1800千米的马萨诸塞州沿海岸线：其一通过2008/2009年彩色航空正射影像（color aerial orthoimagery）勾勒生成，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）数据集提取得到。研究团队将新生成的海岸线数据与马萨诸塞州海岸带管理办公室及美国地质调查局现存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）**计算海岸线长期与短期变迁速率。