The Bathymetry Data Index (BDI) is a catalog of all bathymetry data managed by a mosaic dataset within a Bathymetry Information System (BIS) geodatabase. The mosaic dataset references bathymetry raster data and its supporting tables, including extended, internal, and collection metadata. As you add more bathymetry data to your BIS geodatabase and the BDI, the mosaic dataset calculates footprints for new datasets and updates BDI boundary geometry as necessary. Optimized rendering is provided by the automatic creation of mosaic dataset overviews. Overviews can be thought of as snapshots of the bathymetry datasets at specific scales which are optimized for display speed. Overviews are created automatically to optimize rendering.
Datasets the BDI references can be filtered, by both spatial and attribute metadata information, from the Explore Bathymetry window. Once the bathymetry data is filtered, you can work with the data in the Compose Surface window to define the display order for the bathymetry surface model. When you are finished with your ordered surface model, you can use geoprocessing tools available in the Bathymetry toolbox to derive depth information from the surface and apply it to maritime products.
BDI source datasets
The BDI, like all Esri mosaic datasets, references data from a local disk or network connection. Bathymetry data added to the BIS geodatabase is not physically loaded into the BIS geodatabase; instead, the BDI references the data storage location on disk. This is an efficient storage method and saves disk space, since datasets are not duplicated in the file system and the geodatabase.
Creating the BDI
Adding bathymetry data to the BIS geodatabase with the Add Bathymetry tool updates the existing BDI managed within the BIS geodatabase and creates a new BDI if you are loading bathymetry data for the first time. Before you create the BDI, you should define extended metadata. When you add bathymetry data to the BIS geodatabase, the Add Bathymetry tool performs the following actions:
- Associates the extended and collection metadata with the datasets and stores those links within the BIS geodatabase
- Creates a new or updates the BDI in the BIS geodatabase
- Links bathymetry data to the mosaic dataset, creates pyramids, and computes statistics for better rendering in ArcMap
- Creates the mosaic dataset's boundary
- Calculates cell size ranges for the new BDI
- Calculates the percentage of data coverage
- Defines overviews for the new BDI
After these processes are complete, you can apply filters on the extended, internal, and collection metadata entries within the active BIS geodatabase to retrieve the datasets you want to work with. You can then create rules, based on the metadata fields, which will determine the dataset display order. The combination of filtered datasets and display rules will affect the end result in your final surface model. The surface model, derived from all datasets comprising the BDI, is also a mosaic dataset that can be referenced in a variety of geoprocessing tools or served out as an image service.