AL_TRANSECTS_LT - Long-Term Shoreline Change Rates for Alabama Generated at a 50m Transect Spacing, 1849-2001

Rates of long-term and short-term shoreline change were generated in a GIS with the Digital Shoreline Analysis System (DSAS) version 2.0, an ArcView extension developed by the U.S. Geological Survey (USGS) in cooperation with TPMC Environmental Services. The extension is designed to efficiently lead a user through the major steps of shoreline change analysis. This extension to ArcView contains three main components that define a baseline, generate orthogonal transects at a user-defined separation along the coast, and calculate rates of change (linear regression, endpoint rate, average of rates, average of endpoints, jackknife).

本研究依托地理信息系统（Geographic Information System, GIS）平台，借助美国地质调查局（U.S. Geological Survey, USGS）与TPMC环境服务（TPMC Environmental Services）合作开发的ArcView扩展模块——数字岸线分析系统（Digital Shoreline Analysis System, DSAS）2.0版，生成了长、短期岸线变化速率数据。该扩展模块旨在高效引导用户完成岸线变化分析的核心步骤。这款ArcView扩展模块包含三大核心组件：一是划定基准岸线，二是沿海岸生成用户自定义间距的正交断面（orthogonal transects），三是计算岸线变化速率，涵盖线性回归（linear regression）、端点速率法（endpoint rate）、速率平均值法（average of rates）、端点平均值法（average of endpoints）以及刀切法（jackknife）。