chart datum
Zero depth level
Chart datum is the reference level from which water depths are measured on nautical charts.
It's typically set at the lowest astronomical tide, ensuring that actual water depth will almost always be greater than the charted depth—a safety margin for navigation.
The wreck lies twelve meters below chart datum.
reference
Standard for comparison
- mean sea levelAverage ocean surface height
- zero pointReference baseline value
- baselineStandard for comparison
- ellipsoidOval solid shape
hydrographic
Measured water depths
- water depthMeasure of submersion distance
- fathomNautical depth unit
- hydrographic surveyMeasuring and mapping underwater features
- bathymetrySubaqueous topographical measurement
tidal
Forecasts of sea heights
- spring tideExtreme tidal fluctuation
- neap tideLowest tidal range
- high water markGreatest recorded extent
- tidal rangeExtent of tide fluctuation
benchmark
Standard for comparison
- mean sea levelAverage ocean surface height
- zero pointReference baseline value
- baselineStandard for comparison
soundings
Measured water depths
- water depthMeasure of submersion distance
- fathomNautical depth unit
- hydrographic surveyMeasuring and mapping underwater features
bathymetry · lead line · shoal · hydrographer
tide tables
Forecasts of sea heights
- spring tideExtreme tidal fluctuation
- neap tideLowest tidal range
- high water markGreatest recorded extent
pilotage
Ship navigation expertise
- navigation termsGPS, north, road signs, maps, south
- depth measurementdepth, sounding, depth sensor, depth gauge, depth finder
- reference pointsbenchmark, reference line, reference point, anchor point, control point
- tidal termstide, wave, neap tide, ebb, flow
- tideshigh tide, low tide, ebb tide, tides, flood tide
- hydrographyhydrography, bathymetry, soundings, depth sounding, echo sounder
vertical reference level
chart datumhigh tide
Maximum sea level
mean sea level · crest · peak · flood tide · king tide
chart, data, charts, charter, charting, charted, chartered, chartering, datum