AL_BASELINE - Offshore Baseline for Alabama Generated to Calculate Shoreline Change Rates

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).本数据集的长期与短期海岸线变化速率，依托地理信息系统（GIS）平台，由美国地质调查局（USGS）与TPMC环境服务公司联合开发的ArcView扩展插件——数字海岸线分析系统（Digital Shoreline Analysis System, DSAS）2.0版计算生成。该扩展插件专为高效引导用户完成海岸线变化分析的核心步骤而设计，包含三大核心功能模块：可划定海岸线基线、可沿海岸生成用户自定义间隔的正交断面，同时支持多种变化速率计算方法，包括线性回归法、端点速率法、速率平均值法、端点平均值法以及刀切法（jackknife）。