Onderwerp: LAT / Middenstandsvlak

Middenstandsvlak is gelijk aan NAP????

Wat is de reden dat op zeekaarten de hoogte van objecten (b.v. vuurtorens) vanuit het middenstandsvlak wordt aangegeven en niet vanuit LAT?

Wat is de reden dat op zeekaarten de hoogte van objecten (b.v. vuurtorens) vanuit het middenstandsvlak wordt aangegeven en niet vanuit LAT?

Ik bedoel....
Als wel LAT wordt gebruikt kunnen we dat hele middenstandsvlak overboord kieperen.
Wordt het allemaal weer wat eenvoudiger van.....of is dat nou net niet de bedoeling?

Vinni

Depths and heights
Use of colour in British Admiralty charts

Depths which have been measured are indicated by the numbers shown on the chart. Depths on charts published in most parts of the world use metres. Older charts, as well as those published by the United States government, may use feet or fathoms. Depth contour lines show the shape of underwater relief. Coloured areas of the sea emphasise shallow water and dangerous underwater obstructions. Depths are measured from the chart datum, which is related to the local sea level. The chart datum varies according to the standard used by each national Hydrographic Office. In general, the move is towards using lowest astronomical tide (LAT), the lowest tide predicted in the full tidal cycle, but in non-tidal areas and some tidal areas Mean Sea Level (MSL) is used.

Heights, e.g. a lighthouse, are generally given relative to mean high water spring (MHWS). Vertical clearances, e.g. below a bridge or cable, are given relative to highest astronomical tide (HAT). The chart will indicate what datum is in use.

The use of HAT for heights and LAT for depths, means that the mariner can quickly look at the chart to ensure that they have sufficient clearance to pass any obstruction, though they may have to calculate height of tide to ensure their safety.