North Sea Chart

A hydrographic chart is a geographical map that includes the following important information: troughs, channels, fairways and buoyage.

These hydrographic charts, which are usually yellow nowadays, specify latitude and longitude as well as coastlines, possible shallow areas along the coast and in rivers, sand banks, buoys, beacons, and shallows with their measurements. Troughs and shallows, in particular along coastlines, are outlined with depth contours indicating the varying depths of the water; they are comparable to weather map isobars of high and low pressure areas. Depth measurements are given on the maps, usually in meters.


Example of a Hydrographic Chart, scale 1:375000. (© Hydrografisch Bureau)

For a free online webbapp with hydrographic charts, see;





Name author: AHR
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