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Portolan
Portolan charts are nautical charts, first made in the 13th century in the Mediterranean basin and later expanded to include other regions. The word ''portolan'' comes from the Italian ''portulano'', meaning "related to ports or harbors", and which since at least the 17th century designates "a collection of sailing directions". Definition The term “portolan chart” was coined in the 1890s because at the time it was assumed that these maps were related to portolani, medieval or early modern books of sailing directions. Other names that have been proposed include rhumb line charts, compass charts or loxodromic charts whereas modern French scholars prefer to call them nautical charts to avoid any relationship with portolani. Several definitions of portolan chart coexist in the literature. A narrow definition includes only medieval or, at the latest, early modern sea charts (i.e. maps that primarily cover maritime rather than inland regions) that include a network of rhumb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Portolani
A rutter is a mariner's handbook of written sailing directions. Before the advent of nautical charts, rutters were the primary store of geographic information for maritime navigation. It was known as a ''periplus'' ("sailing-around" book) in classical antiquity and a ''portolano'' ("port book") to medieval Italian sailors in the Mediterranean Sea. Portuguese navigators of the 16th century called it a ''roteiro'', the French a ''routier'', from which the English word "rutter" is derived. In Dutch, it was called a ''leeskarte'' ("reading chart"), in German a ''Seebuch'' ("sea book"), and in Spanish a ''derrotero''. History Before the advent of nautical charts in the 14th century, navigation at sea relied on the accumulated knowledge of navigators and pilots. Plotting a course at sea required knowing the direction and distance between point A and point B. Knowledge of where places lay relative to each other was acquired by mariners during their long experience at sea. The earl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhumbline Network
A rhumbline network, more properly called, a windrose network, or sometimes also called harbour-finding chart, compass chart, or rhumb chart, is a navigational aid drawn on early portolan charts dating from the medieval to early modern period. This network is like a web (see picture) forming a grid on the map. Before accurate surveying there was no method for measuring longitude at sea so maps possessed many distortions especially in the east west direction. There was also distortion due to the curvature of the Earth's surface. The multitude of compass roses with straight lines extending outwards across the map derived from how the maps were then made by compiling empirical observations from navigators who attempted to follow a constant bearing at sea. To calculate a course to follow from a ship's position to a point of desired destination, one would identify the windrose thought to be closest to the ship's position. Then, using a parallel rule, the "line of course" taken f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhumbline Network
A rhumbline network, more properly called, a windrose network, or sometimes also called harbour-finding chart, compass chart, or rhumb chart, is a navigational aid drawn on early portolan charts dating from the medieval to early modern period. This network is like a web (see picture) forming a grid on the map. Before accurate surveying there was no method for measuring longitude at sea so maps possessed many distortions especially in the east west direction. There was also distortion due to the curvature of the Earth's surface. The multitude of compass roses with straight lines extending outwards across the map derived from how the maps were then made by compiling empirical observations from navigators who attempted to follow a constant bearing at sea. To calculate a course to follow from a ship's position to a point of desired destination, one would identify the windrose thought to be closest to the ship's position. Then, using a parallel rule, the "line of course" taken f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Windrose Line
A rhumbline network, more properly called, a windrose network, or sometimes also called harbour-finding chart, compass chart, or rhumb chart, is a navigational aid drawn on early portolan charts dating from the medieval to early modern period. This network is like a web (see picture) forming a grid on the map. Before accurate surveying there was no method for measuring longitude at sea so maps possessed many distortions especially in the east west direction. There was also distortion due to the curvature of the Earth's surface. The multitude of compass roses with straight lines extending outwards across the map derived from how the maps were then made by compiling empirical observations from navigators who attempted to follow a constant bearing at sea. To calculate a course to follow from a ship's position to a point of desired destination, one would identify the windrose thought to be closest to the ship's position. Then, using a parallel rule, the "line of course" taken ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nautical Chart
A nautical chart is a graphic representation of a sea area and adjacent coastal regions. Depending on the scale of the chart, it may show depths of water and heights of land ( topographic map), natural features of the seabed, details of the coastline, navigational hazards, locations of natural and human-made aids to navigation, information on tides and currents, local details of the Earth's magnetic field, and human-made structures such as harbours, buildings, and bridges. Nautical charts are essential tools for marine navigation; many countries require vessels, especially commercial ships, to carry them. Nautical charting may take the form of charts printed on paper (raster navigational charts) or computerized electronic navigational charts. Recent technologies have made available paper charts which are printed "on demand" with cartographic data that has been downloaded to the commercial printing company as recently as the night before printing. With each daily download, crit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nautical Chart
A nautical chart is a graphic representation of a sea area and adjacent coastal regions. Depending on the scale of the chart, it may show depths of water and heights of land ( topographic map), natural features of the seabed, details of the coastline, navigational hazards, locations of natural and human-made aids to navigation, information on tides and currents, local details of the Earth's magnetic field, and human-made structures such as harbours, buildings, and bridges. Nautical charts are essential tools for marine navigation; many countries require vessels, especially commercial ships, to carry them. Nautical charting may take the form of charts printed on paper (raster navigational charts) or computerized electronic navigational charts. Recent technologies have made available paper charts which are printed "on demand" with cartographic data that has been downloaded to the commercial printing company as recently as the night before printing. With each daily download, crit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Loxodromic Navigation
Loxodromic navigation (from Greek ''λοξóς'', oblique, and ''δρóμος'', path) is a method of navigation by following a rhumb line, a curve on the surface of the Earth that follows the same angle at the intersection with each meridian. This serves to maintain a steady course in sailing. Navigating on a spherical surface with a fixed course (\beta in the figure) results in a spiral path that approaches the North Pole for courses ranging from 270º to 090º and the South Pole for courses from 090º to 270º. On a nautical chart plotted according to the Mercator projection, a loxodromic course appears as a straight line. Comparison Chart See also * Great circle navigation * Windrose network * Map * Portolan map * Marine sandglass * Compass rose A compass rose, sometimes called a wind rose, rose of the winds or compass star, is a figure on a compass, map, nautical chart, or monument used to display the orientation of the cardinal directions (north, east, s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compass Rose
A compass rose, sometimes called a wind rose, rose of the winds or compass star, is a figure on a compass, map, nautical chart, or monument used to display the orientation of the cardinal directions (north, east, south, and west) and their intermediate points. It is also the term for the graduated markings found on the traditional magnetic compass. Today, a form of compass rose is found on, or featured in, almost all navigation systems, including nautical charts, non-directional beacons (NDB), VHF omnidirectional range (VOR) systems, global-positioning systems (GPS), and similar equipment. Types Linguistic anthropological studies have shown that most human communities have four points of cardinal direction. The names given to these directions are usually derived from either locally-specific geographic features (e.g. "towards the hills", "towards the sea") or from celestial bodies (especially the sun) or from atmospheric features (winds, temperature). Most mobile populatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vellum
Vellum is prepared animal skin or membrane, typically used as writing material. Parchment is another term for this material, from which vellum is sometimes distinguished, when it is made from calfskin, as opposed to that made from other animals, or otherwise being of higher quality. Vellum is prepared for writing or printing on, to produce single pages, scrolls, codices, or books. Modern scholars and custodians increasingly use only the less specific, potentially-confusing term "membrane".Stokes and Almagno 2001, 114Clemens and Graham 2007, pp. 9–10. Depending on factors such as the method of preparation it may be very hard to determine the animal species involved (let alone its age) without using a laboratory, and the term avoids the need to distinguish between vellum and parchment. Vellum is generally smooth and durable, although there are great variations depending on preparation and the quality of the skin. The manufacture involves the cleaning, bleaching, stretching ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Open Ocean
The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or water column between the surface of the sea and the bottom. Conditions in the water column change with depth: pressure increases; temperature and light decrease; salinity, oxygen, micronutrients (such as iron, magnesium and calcium) all change. Marine life is affected by bathymetry (underwater topography) such as the seafloor, shoreline, or a submarine seamount, as well as by proximity to the boundary between the ocean and the atmosphere at the ocean surface, which brings light for photosynthesis, predation from above, and wind stirring up waves and setting currents in motion. The pelagic zone refers to the open, free waters away from the shore, where marine life can swim freely in any direction unhindered by topographical constraints. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mercator Projection
The Mercator projection () is a cylindrical map projection presented by Flemish geographer and cartographer Gerardus Mercator in 1569. It became the standard map projection for navigation because it is unique in representing north as up and south as down everywhere while preserving local directions and shapes. The map is thereby conformal. As a side effect, the Mercator projection inflates the size of objects away from the equator. This inflation is very small near the equator but accelerates with increasing latitude to become infinite at the poles. As a result, landmasses such as Greenland, Antarctica and Russia appear far larger than they actually are relative to landmasses near the equator, such as Central Africa. History There is some controversy over the origins of the Mercator. German polymath Erhard Etzlaub engraved miniature "compass maps" (about 10×8 cm) of Europe and parts of Africa that spanned latitudes 0°–67° to allow adjustment of his portable pock ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Black Sea
The Black Sea is a marginal mediterranean sea of the Atlantic Ocean lying between Europe and Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. It is bounded by Bulgaria, Georgia, Romania, Russia, Turkey, and Ukraine. The Black Sea is supplied by major rivers, principally the Danube, Dnieper, and Don. Consequently, while six countries have a coastline on the sea, its drainage basin includes parts of 24 countries in Europe. The Black Sea covers (not including the Sea of Azov), has a maximum depth of , and a volume of . Most of its coasts ascend rapidly. These rises are the Pontic Mountains to the south, bar the southwest-facing peninsulas, the Caucasus Mountains to the east, and the Crimean Mountains to the mid-north. In the west, the coast is generally small floodplains below foothills such as the Strandzha; Cape Emine, a dwindling of the east end of the Balkan Mountains; and the Dobruja Plateau considerably ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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