NCEI Bathymetric Attributed Grid (BAG) Mosaic

This image service provides a seamless mosaic of high-resolution quality-controlled seafloor elevation from NOAA National Ocean Service (NOS) Hydrographic Survey Bathymetric Attributed Grids (BAGs) in U.S. coastal waters. Many near-shore areas have been mapped at high resolution (often 1 meter or better). The depths are usually relative to Mean Lower Low Water (MLLW) datum. BAG is a non-proprietary file format for storing and exchanging bathymetric data developed by the Open Navigation Surface Working Group. BAG files are gridded, multi-dimensional bathymetric data files and is the standard NOS hydrographic data file for public release. Current versions of the BAG file contain position and depth grid data, as well as position and uncertainty grid data, and the metadata specific to that BAG file, providing end users information about the source and contents of the BAG file. The corresponding NOS Hydrographic Surveys map service displays the locations and coverage of the hydrographic surveys as polygons, along with additional metadata and links to obtain the data. This image service is available in 3 versions: Tile Layer (overview of all surveys in a continuous image) Note: this is a tiled image service, cached to zoom level 14. Dynamic Image Service (overview of all surveys in a continuous image) Subsets version (access to the underlying images; allows subsets using a definition query; maximum of 80 rasters displayed at a time) This service has several server-side functions available. These can be selected in the ArcGIS Online layer using "Image Display", or in ArcMap under "Processing Templates". None: Provides depth values in meters. Usually relative to mean lower low water (MLLW), except for some rivers/lakes (see the survey metadata for details). ColorHillshadeBAG: An elevation-tinted hillshade visualization. This is also available as a separate tile layer (faster to draw). The depths are displayed using this color ramp: The NCEI Bathymetric Data Viewer (NOAA GeoPlatform entry) can be used to search and display these data. More information about NOS Hydrographic Survey data available at NCEI. Last update: July 22, 2026本影像服务提供美国沿海水域内，由美国国家海洋和大气管理局（National Oceanic and Atmospheric Administration, NOAA）国家海洋服务局（National Ocean Service, NOS）海道测量测深属性网格（Bathymetric Attributed Grids, BAGs）生成的、经过质量控制的高分辨率海底高程无缝镶嵌图。诸多近岸区域已完成高分辨率测绘（分辨率通常可达1米及更高）。水深数据通常基于平均低低潮面（Mean Lower Low Water, MLLW）基准面。 BAG是由开放导航表面工作组（Open Navigation Surface Working Group）开发的非专有文件格式，用于存储与交换测深数据。BAG文件为网格化多维测深数据文件，是NOS面向公众发布的标准海道测量数据文件格式。当前版本的BAG文件包含位置与水深栅格数据、位置与不确定性栅格数据，以及对应BAG文件的专属元数据，可为终端用户提供该文件的来源与内容相关信息。 配套的NOS海道测量地图服务以多边形形式展示海道测量项目的位置与覆盖范围，同时附带额外元数据及数据获取链接。 本影像服务共提供三种版本： 1. 瓦片图层（以连续影像形式展示全部测绘概况）注：本服务为瓦片影像服务，缓存至缩放级别14； 2. 动态影像服务（以连续影像形式展示全部测绘概况）； 3. 子集版本（可访问底层影像；支持通过定义查询进行子集提取；单次最多显示80幅栅格）。 本服务提供多项服务端功能，可在ArcGIS Online图层中通过"影像显示"选项调用，或在ArcMap的"处理模板"下选择： - None：以米为单位提供水深值。通常基于平均低低潮面（MLLW）基准面，部分河流、湖泊除外（详见测绘元数据）； - ColorHillshadeBAG：基于高程着色的山体阴影可视化效果，亦可作为独立瓦片图层使用（绘制速度更快）。水深采用以下色阶进行展示： NCEI测深数据查看器（NOAA地理平台入口）可用于搜索并展示此类数据。有关NOS海道测量数据的更多信息可在NCEI查询获取。 最后更新日期：2026年7月22日