Nantucket_intersects_STlr.shp - Digital Shoreline Analysis System version 4.3 shoreline intersection points used to calculate short-term (Linear Regression Rate) shoreline change statistics within the Nantucket coastal region including the Nantucket Sound- and Atlantic Ocean- facing coasts of Nantu

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 in total length) 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，以支撑海岸线与洪泛区的管理决策。1989年，马萨诸塞州海岸带管理局（Massachusetts Office of Coastal Zone Management）启动了海岸线变化项目（Shoreline Change Project），旨在识别海岸沿线的侵蚀易发区域。2001年，研究团队新增1994年的海岸线数据，用于计算马萨诸塞州面向开阔海域的海岸段上每40米间隔处的长期与短期海岸线变迁速率。
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局合作，依托《马萨诸塞州海岸线变化制图与分析项目2013年更新版》，汇编了马萨诸塞州面向开阔海域的海岸段的可靠历史海岸线数据集。该数据集包含两条马萨诸塞州海滨海岸线（总长度约1800公里）：其一通过2008/2009年的彩色航空正射影像进行数字化勾绘，其二则从美国国家海洋和大气管理局（NOAA）海洋服务局海岸服务中心获取的2007年地形LIDAR数据集当中提取得到。研究团队将新获取的海岸线数据与马萨诸塞州海岸带管理局及美国地质调查局现存的历史海岸线数据集进行整合，依托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迁速率。