Nautical Charts
Nautical charts are a graphical representation of any and all features in a particular waterway. These may include landforms, sunken vessels, bridges, coastline data and tidal patterns. There is a plethora of information on the documents, making them essential for safe navigation on the water. In the past, they have always been printed out on paper for easy access by a boat’s navigator or captain. However, due to changing conditions, this have not been proven to be totally reliable. Nowadays, most countries require the charts to be on board at all times. But recent advancements in technology allow this information to be updated on a nightly basis, so the data contained is 100% accurate for the day’s sailing. Most of the time, a hydrographic survey is used to measure the different depths of water and various data in a particular body of water. However, since these are quite expensive and labor intensive, they don’t get updated very often. Of course, this leads to outdated information that is not always reliable. That is another reason why the electronic versions of these maps have been relied on the fill the void between surveys. A fresh set of data can be printed out for the days voyage in most areas of water. There are a great many varieties of nautical charts for seafarers to use, including commercial and free types. NOAA (National Ocean and Atmospheric Administration) offers a free version that can be downloaded and printed from a home computer. Their service includes the entire U.S. coastline and are continuously updated. They do not however, offer as much detail as the full size type does. OpenSeaMap is another free chart that is part of the open source wiki project and offers mariners worldwide the chance to update the offerings with new information. It covers waterways worldwide and has details regarding buoy placement, harbor lights and other assorted data that is useful to seagoing men. MarineGeoGarage is a free web-based application that links up the various hydrographic surveys in one place. The official nautical chart is issued by the hydrographic office in most countries. Many offer weekly or monthly updates via their distribution agents. These are highly detailed, graphical representations of the surrounding body of water. They can also publish a national or international document of this type if needed. Government offices offer their own version of the nautical chart. There are 3 separate agencies that publish this information, however, all of them offer a slightly different type. NOAA, as mentioned previously is U.S. based and used information to map domestic charts for American citizens. NIMA (National Imagery and Mapping Agency ) offers the international type for ocean going vessels. OceanGrafix uses the information from the NOAA charts to supply charts on demand. These can be printed out as needed. The right type of chart is based upon the area currently being navigated. It is up to the captain to obtain this information before sailing to ensure a safe passage for all crew members.
