Reading a seabed through sound
A sonar return is a measurement, not a picture of the ocean floor. Turning it into a useful chart means accounting for the water, the moving vessel, and what the echo cannot identify on its own.
Follow a thread
Hydrography
2 stories found Clear filters ↗
The archive
2 storiesHydrography
The zero beneath a harbour
Chart datum connects a sounding to a tide height. Its local reference, time period and uncertainty explain why the zero beneath a harbour needs a name.