Its traditional purpose was to hold the ships magnetic compass, mounted in gimbals to keep it level while the ship pitched and rolled. A binnacle may be subdivided into sections and its contents include one or more compasses. Other devices such as a timer for estimating speed may have been stored in the binnacle as well. The construction of many early binnacles used iron nails, which were discovered to cause magnetic deviations in compass readings. As the development of the compass and understanding of magnetism progressed, with the introduction of iron-clad ships the magnetic deviation observed in compasses became more severe. Methods of compensation by arranging iron or magnetic objects near the binnacle were developed, in 1854, a new type of binnacle was patented by John Gray of Liverpool which directly incorporated adjustable correcting magnets on screws or rack and pinions. This was improved again when Lord Kelvin patented in the 1880s another system of compass and these are colloquially known as Kelvins balls in the UK, and navigators balls in the United States.
Unlike most display binnacles today, which have the balls painted red and green to represent port and starboard side of the vessel, the Royal Maritime museum at Greenwich, has an extensive collection of binnacles in correct colours. The ships binnacle list is the medical report of personnel at sick bay. Before 18th century bittacle, through French bitacle, from Latin habitaculum, logbook Gyrocompass Media related to Binnacles at Wikimedia Commons Alan Gurney, Compass, A Story of Exploration and Innovation, W. W. Norton & Company,2004, ISBN 0-393-32713-2, from the Querencia Chronicles, The Binnacle Chisholm, Hugh, ed. Binnacle
Port and starboard
Port and starboard are nautical and aeronautical terms for left and right, respectively. Port is the side of a vessel or aircraft, facing forward. Starboard is the side, facing forward. Since port and starboard never change, they are references that are not relative to the observer. These terms are being used as aeronautic terms, the term starboard derives from the Old English steorbord, meaning the side on which the ship is steered. Before ships had rudders on their centrelines, they were steered with an oar at the stern of the ship and, because more people are right-handed. The term is cognate with the Old Norse stýri and borð, since the steering oar was on the right side of the boat, it would tie up at wharf on the other side. Hence the left side was called port, larboard was used instead of port. This is from Middle-English ladebord and the lade is related to the modern load. Larboard sounds similar to starboard and in 1844 the Royal Navy ordered that port be used instead, the United States Navy followed suit in 1846.
Larboard continued to be used well into the 1850s by whalers, in Old English the word was bæcbord, of which cognates are used in other European languages, for example as the present Dutch bakboord, the German backbord and the French term bâbord. Aircraft are lit in the same way
Geography is a field of science devoted to the study of the lands, the features, the inhabitants, and the phenomena of Earth. The first person to use the word γεωγραφία was Eratosthenes, Geography is an all-encompassing discipline that seeks an understanding of the Earth and its human and natural complexities—not merely where objects are, but how they have changed and come to be. It is often defined in terms of the two branches of geography and physical geography. Geography has been called the world discipline and the bridge between the human and the physical sciences, Geography is a systematic study of the Earth and its features. Traditionally, geography has been associated with cartography and place names, although many geographers are trained in toponymy and cartology, this is not their main preoccupation. Geographers study the space and the temporal database distribution of phenomena, because space and place affect a variety of topics, such as economics, climate and animals, geography is highly interdisciplinary.
The interdisciplinary nature of the approach depends on an attentiveness to the relationship between physical and human phenomena and its spatial patterns. Names of places. are not geography. know by heart a whole gazetteer full of them would not, in itself and this is a description of the world—that is Geography. In a word Geography is a Science—a thing not of mere names but of argument and reason, of cause, just as all phenomena exist in time and thus have a history, they exist in space and have a geography. Geography as a discipline can be split broadly into two main fields, human geography and physical geography. The former largely focuses on the environment and how humans create, manage. The latter examines the environment, and how organisms, soil, water. The difference between these led to a third field, environmental geography, which combines physical and human geography. Physical geography focuses on geography as an Earth science and it aims to understand the physical problems and the issues of lithosphere, atmosphere and global flora and fauna patterns.
Physical geography can be divided into broad categories, Human geography is a branch of geography that focuses on the study of patterns. It encompasses the human, cultural, and it requires an understanding of the traditional aspects of physical and human geography, as well as the ways that human societies conceptualize the environment. Integrated geography has emerged as a bridge between the human and the geography, as a result of the increasing specialisation of the two sub-fields. Examples of areas of research in the environmental geography include, emergency management, environmental management, geomatics is concerned with the application of computers to the traditional spatial techniques used in cartography and topography
Plan position indicator
The plan position indicator, is the most common type of radar display. The radar antenna is usually represented in the center of the display, so the distance from it, as the radar antenna rotates, a radial trace on the PPI sweeps in unison with it about the center point. The radar antenna sends pulses while rotating 360 degrees around the site at a fixed elevation angle. It can change angle or repeat at the same according to the need. Return echoes from targets are received by the antenna and processed by the receiver and it is to be noted that the height of the echoes increases with the distance to the radar, as represented in the adjacent image. This change is not a line but a curve as the surface of the Earth is curved. For fixed-site installations, north is usually represented at the top of the image. For moving installations, such as ship and aircraft radars, the top may represent the bow or nose of the ship or aircraft, i. e. its heading. Some systems may incorporate the input from a gyrocompass to rotate the display, the signal represented is the reflectivity at only one elevation of the antenna, so it is possible to have many PPIs at one time, one for each antenna elevation.
The PPI display was first used prior to the start of the Second World War in a Jagdschloss experimental radar system outside Berlin, the first production PPI was devised at the Telecommunications Research Establishment, UK and was first introduced in the H2S radar blind-bombing system of World War II. Originally, data was displayed in real time on a cathode ray tube, philo Taylor Farnsworth, the American inventor of all-electronic television in September 1927, contributed to this in an important way. Farnsworth refined a version of his picture tube and called it an Iatron and it could store an image for milliseconds to minutes and even hours. One version that kept an image alive about a second before fading proved to be useful for radar and this slow-to-fade display tube was used by air traffic controllers from the very beginning of radar usage. With the development of sophisticated radar systems, it became possible to digitize data and store it in memory. The PPI is used in many domains involving display of range and positioning, especially in radars, including air traffic control, ship navigation, meteorology, on board ships, PPI displays are used to display sonar data, especially in underwater warfare.
However, because the speed of sound in water is slow compared to microwaves in air. In meteorology, a display system is the CAPPI when a multi-angle scan is available. Using computers to process data, modern sonar and lidar installations can mimic radar PPI displays too, sir Bernard Lovell ECHOES OF WAR, The Story of H2S Radar ISBN 0-85274-317-3 Adapted from Microwave Radar At War
Radar is an object-detection system that uses radio waves to determine the range, angle, or velocity of objects. It can be used to detect aircraft, spacecraft, guided missiles, motor vehicles, weather formations, Radio waves from the transmitter reflect off the object and return to the receiver, giving information about the objects location and speed. Radar was developed secretly for military use by several nations in the period before, the term RADAR was coined in 1940 by the United States Navy as an acronym for RAdio Detection And Ranging or RAdio Direction And Ranging. The term radar has since entered English and other languages as a common noun, high tech radar systems are associated with digital signal processing, machine learning and are capable of extracting useful information from very high noise levels. Other systems similar to make use of other parts of the electromagnetic spectrum. One example is lidar, which uses ultraviolet, visible, or near infrared light from lasers rather than radio waves, as early as 1886, German physicist Heinrich Hertz showed that radio waves could be reflected from solid objects.
In 1895, Alexander Popov, an instructor at the Imperial Russian Navy school in Kronstadt. The next year, he added a spark-gap transmitter, in 1897, while testing this equipment for communicating between two ships in the Baltic Sea, he took note of an interference beat caused by the passage of a third vessel. In his report, Popov wrote that this phenomenon might be used for detecting objects, the German inventor Christian Hülsmeyer was the first to use radio waves to detect the presence of distant metallic objects. In 1904, he demonstrated the feasibility of detecting a ship in dense fog and he obtained a patent for his detection device in April 1904 and a patent for a related amendment for estimating the distance to the ship. He got a British patent on September 23,1904 for a radar system. It operated on a 50 cm wavelength and the radar signal was created via a spark-gap. In 1915, Robert Watson-Watt used radio technology to advance warning to airmen. Watson-Watt became an expert on the use of direction finding as part of his lightning experiments.
As part of ongoing experiments, he asked the new boy, Arnold Frederic Wilkins, Wilkins made an extensive study of available units before selecting a receiver model from the General Post Office. Its instruction manual noted that there was fading when aircraft flew by, in 1922, A. Hoyt Taylor and Leo C. Taylor submitted a report, suggesting that this might be used to detect the presence of ships in low visibility, eight years later, Lawrence A. Australia, New Zealand, and South Africa followed prewar Great Britain, and Hungary had similar developments during the war. Hugon, began developing a radio apparatus, a part of which was installed on the liner Normandie in 1935
A degree, usually denoted by °, is a measurement of a plane angle, defined so that a full rotation is 360 degrees. It is not an SI unit, as the SI unit of measure is the radian. Because a full rotation equals 2π radians, one degree is equivalent to π/180 radians, the original motivation for choosing the degree as a unit of rotations and angles is unknown. One theory states that it is related to the fact that 360 is approximately the number of days in a year. Ancient astronomers noticed that the sun, which follows through the path over the course of the year. Some ancient calendars, such as the Persian calendar, used 360 days for a year, the use of a calendar with 360 days may be related to the use of sexagesimal numbers. The earliest trigonometry, used by the Babylonian astronomers and their Greek successors, was based on chords of a circle, a chord of length equal to the radius made a natural base quantity. One sixtieth of this, using their standard sexagesimal divisions, was a degree, Aristarchus of Samos and Hipparchus seem to have been among the first Greek scientists to exploit Babylonian astronomical knowledge and techniques systematically.
Timocharis, Aristillus and Hipparchus were the first Greeks known to divide the circle in 360 degrees of 60 arc minutes, eratosthenes used a simpler sexagesimal system dividing a circle into 60 parts. Furthermore, it is divisible by every number from 1 to 10 except 7 and this property has many useful applications, such as dividing the world into 24 time zones, each of which is nominally 15° of longitude, to correlate with the established 24-hour day convention. Finally, it may be the case more than one of these factors has come into play. For many practical purposes, a degree is a small enough angle that whole degrees provide sufficient precision. When this is not the case, as in astronomy or for geographic coordinates, degree measurements may be written using decimal degrees, with the symbol behind the decimals. Alternatively, the sexagesimal unit subdivisions can be used. One degree is divided into 60 minutes, and one minute into 60 seconds, use of degrees-minutes-seconds is called DMS notation.
These subdivisions, called the arcminute and arcsecond, are represented by a single and double prime. For example,40. 1875° = 40° 11′ 15″, or, using quotation mark characters, additional precision can be provided using decimals for the arcseconds component. The older system of thirds, etc. which continues the sexagesimal unit subdivision, was used by al-Kashi and other ancient astronomers, but is rarely used today
A compass is an instrument used for navigation and orientation that shows direction relative to the geographic cardinal directions, or points. Usually, a called a compass rose shows the directions north, east. When the compass is used, the rose can be aligned with the geographic directions, so, for example. Frequently, in addition to the rose or sometimes instead of it, North corresponds to zero degrees, and the angles increase clockwise, so east is 90 degrees, south is 180, and west is 270. These numbers allow the compass to show azimuths or bearings, which are stated in this notation. The magnetic compass was first invented as a device for divination as early as the Chinese Han Dynasty, the first usage of a compass recorded in Western Europe and the Islamic world occurred around the early 13th century. The magnetic compass is the most familiar compass type and it functions as a pointer to magnetic north, the local magnetic meridian, because the magnetized needle at its heart aligns itself with the horizontal component of the Earths magnetic field.
The needle is mounted on a pivot point, in better compasses a jewel bearing. When the compass is level, the needle turns until, after a few seconds to allow oscillations to die out. In navigation, directions on maps are usually expressed with reference to geographical or true north, the direction toward the Geographical North Pole, the rotation axis of the Earth. Depending on where the compass is located on the surface of the Earth the angle between north and magnetic north, called magnetic declination can vary widely with geographic location. The local magnetic declination is given on most maps, to allow the map to be oriented with a parallel to true north. The location of the Earths magnetic poles slowly change with time, the effect of this means a map with the latest declination information should be used. Some magnetic compasses include means to compensate for the magnetic declination. The first compasses in ancient Han dynasty China were made of lodestone, the compass was used for navigation during the Song Dynasty of the 11th century.
Later compasses were made of iron needles, magnetized by striking them with a lodestone, dry compasses began to appear around 1300 in Medieval Europe and the Islamic world. This was supplanted in the early 20th century by the magnetic compass. Modern compasses usually use a needle or dial inside a capsule completely filled with a liquid