Bathy DataBase

Source bathymetric data are data as close as possible to their collection stage, but processed to correct the systematic errors and human blunders. The Bathy DataBase (BDB), which CHS introduced in 2011, normalizes and integrates all of CHS’s bathymetric data sources into one system.

These data sources include:

  • Legacy data digitized from historical field sheets and collected by CHS (or British Admiralty) from the end of 19th century to the end of 1980s. The sounding techniques were usually lead line and single-beam echosounder.
  • Recent survey data collected by CHS, which are converted directly from original field data format into some uniform storage. Field sheets may have been produced with these data. Sounding techniques include echosounders, either single-beam, multi-transducer or multibeam.
  • Data of all ages from external organizations for different purposes (e.g., dredging, engineering, coastal management, etc.), provided to CHS via agreements with other government departments, academia or private-sector partners, and transmitted in different formats.
  • Data from special types of sounding methods such as lidar, Through-the-Ice Bathymetric System (TIBS) and spot echosounding.
Example of initial Bathy DataBase view of nautical chart 4826, covering, Ramea Islands, Newfoundland

Example of initial Bathy DataBase view of nautical chart 4826, covering, Ramea Islands, Newfoundland

An example of the Bathy DataBase, after the bathymetric data sources have been loaded into nautical chart 4826, covering, Ramea Islands, in Newfoundland

An example of the Bathy DataBase, after the bathymetric data sources have been loaded into nautical chart 4826, covering, Ramea Islands, in Newfoundland

The BDB system also stores two categories of data: navigational surface, which represents the bathymetry on a regular grid and usually acquired by total coverage echo sounding systems; and sparse, spatially discrete soundings acquired by other depth measurement systems. These two categories of source data sets are loaded in BDB respectively as surfaces or sounding sets (point clouds).

The BDB can also manage backscatter, supplied by multibeam echosounders.

Because of the volume and variety of the source data, the initial loading of any data is a considerable undertaking. All data must be converted into a known data format and adjusted to a common vertical datum (the chart datum). The data are then compared to existing, overlapping datasets and the data most closely representing the seabed are selected for use.