Nautical chart : How to choose your nautical chart
Marine chart: definition
In accordance with the maritime signage, a , or nautical chart, will help you to navigate and find your way at sea. It contains all the elements and information necessary for maritime navigation. A nautical chart takes into account weather conditions, including tides, currents, sea state and hazards on the route. A nautical chart is therefore essential to reach your destination safely.
How do I read a nautical chart?
To read a , you must refer to the nomenclature of your chart and identify the information you need: the colors of the depth zones, the numbers on the probes and the levels, the letters, and the symbols and markings. Knowing how to read geographic coordinates will help you read a chart more accurately.
Depth Zone Colors
On a nautical chart, there are different colors to distinguish the different zones.
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White: these are areas of deep water, that is, waters more than 10 meters deep.
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Blue: these are areas of shallow water, i. e. waters between 0 and 10 meters deep.
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Green: this is the area known as "foreshore", i. e. the strip of coastline that is submerged at high tide, but likely to emerge at low tide.
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Bistre (brown): it is simply the color that represents the dry land.
The different numbers in italics in the blue and white areas correspond to the depth of the latter. They are probes that indicate the minimum depth of water at that location. They are set from level 0, which is the lowest sea level for a tidal coefficient of 120. The first number indicates the number of meters, the second indicates the decimeters. Thus,23 means a depth of 2.3 meters. If the first number is underlined, it means that at the lowest tide, the bottom will be X meters deeper than the value indicated. This is called a negative depth. If the numbers are in parentheses, it means a slight offset between the location shown on the chart and the actual position of the object. This is done so as not to overload the maps if other information is present next to it. The CAPITAL letters that appear in the blue and white areas indicate the nature of the seabed. They are initials from abbreviations of English words and therefore do not necessarily correspond to the French word attached to them. Two letters separated by a / mean a mixed soil. We thus find : S for Sand M for Mud St for Stones G for Gravel P for Pebbles R for Rocks Wd for Seaweed and Grass Sh for Shells The letters in MINUSCULE correspond to the quality of the sea bottom. We find : f for Fine m for Medium sy for Sticky sf for Consistent bk for Broken so for Soft h for Hard We also find many symbols on a nautical chart. Here is a summary and their meaning. All symbols can be found in the 1D book of the SHOM. The letters below the marker indicate the color of the buoy: B for Black W for White G for Green Y for Yellow R for Red Thus, you will be able to find all the following marker symbols: The scale of a chart is usually located at the bottom right or bottom left of the chart. It corresponds to the reduction factor of the map compared to the real. Thus, for a scale of 1:25,000, 1 centimeter on the map will correspond to 25,000 centimeters in reality, or 250 meters. We pronounce this scale one twenty-five thousandth, as presented below: Geographical coordinates (maritime or terrestrial) are always expressed in Longitude(L) and Latitude(L). The Longitude is written first, then the Latitude according to the DMS(Degrees, Minutes, Seconds) system. These coordinates are expressed in degrees, with 1 degree comprising 60 minutes, and 1 minute comprising 60 seconds. 1 minute corresponds to 1 mile which is equivalent to 1.852 km. Longitude: These are the vertical lines on the map, they are called Meridians. East of the Greenwich meridian (0° longitude), the longitude is noted as X°E. West of the Greenwich meridian, longitude is noted as X°W. For example, for a point X of longitude 45°46'23.9" north of the Equator and latitude 4°47'49.8 "E east of Greenwich, we will note it as 45°46'24.6 "N 4°47'51.7 "E. We will read these coordinates as 45 degrees 46 minutes 24 seconds 6 tenths North 4 degrees 47 minutes 51 seconds 7 tenths East. At Nautisports, we offer a wide range of nautical charts from the Navicarte chart to the SHOM chart. You can find them in our dedicated category
. For the Atlantic - Channel area for example, you can find the Navicarte version:
or the SHOM version:
. To stay up to date and not forget anything about the marine code, opt for the anchor_text="Adhesive Marine Code Topoplastic" template="product/widget/link/link_inline.phtml" id_path="product/29359"}}, which groups together all the essential information about marine signage. Finally, due to the mostly paper composition of nautical charts, the
is an indispensable waterproof accessory to protect your nautical chart and SHOM chart from water splashes. You can find all the details, areas covered, material, dimensions of a chart by consulting its product sheet in which all this information appears. Good navigation to all! For any question or additional information, we are with your listening to the 04.78.41.79.31. The Nautisports. com team
The numbers
The letters
The different symbols and markup
The symbols
The markings
Finding your way on a nautical chart
The Scale
Longitude and latitude
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