What is the chart datum to which indian charts are made ?
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Chart Datum is an arbitrary plane below which low water tide seldom falls. It is a datum to which sounding on a published hydrographic chart are reduced. All the bathymetric contours are referred to this datum. The tidal predictions and tidal levels given in the tide tables are also given with relation to the same datum. Chart datum in India had been fixed at Indian Spring Low Water Mark (ISLW) during nineteenth century. For this, sufficiently long tidal observations had been made at various locations. During the Spring tide, low water mark had been measured and fixed as chart datum at this location
MMD / MCA ORALS 2ND MATE EXAM
