
SDB-Online – developed within the 4S project – aims to empower shallow water and coastal stakeholders to rapidly map and monitor shallow water environments – with the comfort of a desktop study. This concept has been applied and tested in 16 use cases in nine countries all over the world. For this purpose, SDB-Online created bathymetric surfaces in 10-meters spatial resolution for all of the sites, independent from local survey or ground truth data.
Later, the project team assessed and validated bathymetric results from SDB-Online by comparison with in-situ data. Subsequently, this process helped to continuously improve the WebApp. The selected use cases below showcase the proof of concept for different mapping and monitoring environments:
Use Case Hooper Inlet

Satellite-Derived Bathymetry chart of the coast at Hooper, in the high latitudes of Canada
This use case showcases the validity of SDB-Online data in the high latitudes of Canada. The following two figures illustrate the SDB results and the scatterplot of SDB versus traditional bathymetry survey data.

Scatterplot of bathymetry by SDB-Online validated against in-situ data of Hooper, Can.
For Hooper, Canada, SDB data were mapped from shoreline down to approximately 12 to 15 meters (LAT). The SDB in the very shallow waters allows to fill data gaps of the acoustic survey.
Interesting finding: On this site, a shoal could be identified and mapped in the SDB data (centre). Its spatial dimension was not present in the single beam echo sounder survey.
Use Case Dublin Bay

Satellite-Derived Bathymetry of Dublin Bay – c/EOMAP for S4
Dublin Bay use case shows the validity of SDB data in rather turbid waters. The following two figures illustrate the SDB results and the scatterplot of SDB versus traditional bathymetry survey data at the 4S use case in Dublin Bay, Ireland.

Validation scatterplot of SDB in Dublin Bay, IReland
Dublin Bay’s water clarity allowed to apply Satellite-Derived Bathymetry to map the seafloor down to 7.8 m at the time of satellite image recording. This equals to 5 meters below LAT, whereas the MBES survey data did not cover the intertidal depth.
Interesting finding: On this coastal site with higher turbidity, the combination of both surveys allowed for a seamless bathymetric grid from +3 meters LAT down to deeper water.
Use Case Sint Maarten, Caribbean

Satellite-Derived Bathymetry chart of Sint Maarten, SX – c/EOMAP for 4S
The use case of Sint Maarten – a coastline in the Caribbean – represented the water conditions with the clearest waters.

Validation plot of the use case in the Netherland Antilles.
The following two figures illustrate the SDB results and the scatterplot of SDB versus traditional bathymetry survey data at the 4S use case in the cristal clear waters of the Netherland Antilles.
The extremely high water clarity of these Caribbean waters allowed to apply Satellite-Derived Bathymetry to map the seafloor down to 20 meters depth.
Read more about the robust technology behind SDB-Online.