The following terms apply to bathymetric data, products, and workflow management.
Bathymetry is the measurement of underwater depths and the description of landforms beneath a body of water. This information is gathered from 3D and profile analysis of depth data.
Bathymetric Attributed Grid file (BAG)
Gridded data formatted as a Bathymetric Attributed Grid (BAG) is a multidimensional hydrographic data file that meets standards developed by the Open Navigation Surface Working Group. BAG files contain elevation gridded data and Total Propagated Uncertainty (TPU) gridded data, as well as metadata.
Bathymetric Data Index (BisBDI)
The BIS Bathymetric Data Index (BisBDI) is a mosaic dataset that maintains a list of all gridded surfaces registered in the Bathymetric Information System (BIS) geodatabase. The BDI mosaic dataset is created by running the BIS To Mosaic Dataset tool without an optional query file. It is managed apart from the main framework of the BIS. Since the mosaic datasets manage the location of gridded surfaces rather than loading the datasets directly into the geodatabase, file system data storage requirements are greatly reduced. Subsequent surfaces can be generated from the BDI using the Bathymetry web app, which can be found in the product files.
Bathymetric Information System (BIS)
A BIS is a geodatabase containing a catalog of all spatial data being managed with the ArcGIS Bathymetry extension. Since the BIS manages the location of datasets rather than loading the datasets directly into the geodatabase, file system data storage requirements are greatly reduced. BIS data can be vector or grid. BIS grid data can be used to create customized bathymetric surfaces with other tools provided in the extension.
Bathymetry web app
A configurable web app that uses an image service published from the BisBDI to allow users to perform filter and sort operations on gridded bathymetric data. Filter, rule, and model recipes can be saved and reused in the web app or with geoprocessing tools in ArcGIS Bathymetry.
A hydrographic survey is the measurement and description of water masses, water depths, the nature of the seabed, currents, tides, and other physical features of the ocean. Results from hydrographic surveys are used for navigation safety, ocean and coastal engineering, environmental protection, coastal zone management, marine archaeology, naval operations, and ocean sciences. Typically, hydrographic vessels conduct these surveys using echo sounding equipment; increasingly, surveys include light detection and ranging (lidar) bathymetry from aircraft and sophisticated electronic sensor systems in clear and shallow waters.
Soundings are depth measurements taken from the surface through a water column, generated when a mariner or a machine sends a probe into the ocean. Historically, soundings were taken from simple instruments such as lead lines; today, mariners can collect echo soundings.
The BAG file specification requires an uncertainty grid coincident with depth information. The uncertainty grid is a two-dimensional array of positive values, given in units of meters, that describes the vertical uncertainty at every pixel for which an elevation value is also present.