Bathymetry 2 Hydrographic surveys 2 Survey vessels Bathymetric survey 1 Beaches 1 Condition 1 Cross-track errors 1 Digital Sea Bottom Model 1 Digital sea bottom model 1 Echo sounders 1 Electronic Navigational Chart 1 Electronic navigational chart 1 Engineering structures 1 Geodesy 1 Geodetic satellites 1 Global positioning system 1 Line keeping 1 Minimum safe distance 1 Motor boats 1 Navigation 1 Offshore area 1 Offshore oil well production 1 Positioning 1 Sea bottom 1 Shallow waters 1 Survey line 1 Survey planning 1 USV 1 Unmanned survey vessel 1 Water areas 1