Delineated Coastal Cliff Tops Derived from Post-Hurricane Maria Lidar Elevation Data Collected from Puerto Rico: 2018

The National Assessment of Coastal Change Hazards project aims to understand and forecast coastal landscape change. This dataset consists of delineated coastal cliff tops that may be used to assess the hazard posed by eroding coastal cliffs on the islands of Puerto Rico, Culebra, and Vieques. The delineation of cliff tops and toes can be used as an input into cliff hazard metrics and to measure overall cliff changes over time. Cliff tops and cliff toes were identified along three-dimensional (3D) transects using the Cliff Feature Delineation Tool (Seymour and others, 2020), which assigned coordinate locations (X, Y, Z) of cliff features over a 140,244-meter (m) stretch of the Puerto Rican coastline at 10-m intervals and output them as either polyline (cliff transects) or point (cliff top or toe) shapefiles. Feature delineation was performed using post-Hurricane Maria (landfall was September 20, 2017) rasterized topobathy lidar elevation data collected by the U.S. Army Corps of Engineers and published by the National Oceanic and Atmospheric Administration National Centers for Environmental Information (2018) as bare earth digital elevation model (DEM) files. The delineation tool (Seymour and others, 2020) was used to generate 3D point features in Esri ArcGIS shapefile format representing the cliff tops; these files should be opened in a 3D geographic information system (GIS) viewer.

国家海岸变化灾害评估项目（National Assessment of Coastal Change Hazards）旨在研判并预测海岸景观演变态势。本数据集包含经标绘的海岸悬崖顶数据，可用于评估波多黎各岛、库莱布拉岛以及别克斯岛受侵蚀海岸悬崖所引发的灾害风险。悬崖顶与崖脚的标绘成果可作为悬崖灾害评估指标的输入项，同时可用于量化悬崖随时间推移的整体变化情况。研究团队使用悬崖特征标绘工具（Cliff Feature Delineation Tool，Seymour等，2020），沿三维（3D）断面识别了悬崖顶与崖脚：该工具以10米为间隔，在波多黎各沿岸总长140244米的岸段上获取了悬崖特征的三维坐标（X、Y、Z），并将结果输出为折线（悬崖断面）或点（悬崖顶或崖脚）格式的形状文件（shapefile）。特征标绘工作基于飓风“玛丽亚”（2017年9月20日登陆）后的栅格化激光雷达地形水深高程数据开展，该数据由美国陆军工程兵团采集，由美国国家海洋和大气管理局国家环境信息中心（2018）以裸地数字高程模型（digital elevation model, DEM）文件形式发布。本研究使用该标绘工具（Seymour等，2020）生成了以Esri ArcGIS形状文件格式存储的悬崖顶三维点要素，此类文件需通过三维地理信息系统（geographic information system, GIS）浏览器打开。