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Hand Bearing Compass
A bearing compass, is a nautical instrument used to determine the bearing of observed objects. (Bearing: angle formed by the north and the visual to a certain object in the sea or ashore). Used in navigation to determine the angle between the direction of an object and the magnetic north or, indirectly relative to another reference point. Provides the absolute bearing, which is the clockwise angle between magnetic north or true north and the object. For example, an object to the east would have an absolute bearing of 90º, if it is relative to the magnetic north than it is called magnetic bearing. It is commonly used by geologists and surveyors to obtain precise bearings on the ground. Sailors use successive demarcations of fixed reference points along with simple geometric techniques to determine their position, course and speed. In addition, making successive demarcations of other vessels, together with simple geometry techniques, can help the navigator to determine if there ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Binoculars
Binoculars or field glasses are two refracting telescopes mounted side-by-side and aligned to point in the same direction, allowing the viewer to use both eyes (binocular vision) when viewing distant objects. Most binoculars are sized to be held using both hands, although sizes vary widely from opera glasses to large pedestal-mounted military models. Unlike a (monocular) telescope, binoculars give users a stereopsis, three-dimensional image: each eyepiece presents a slightly different image to each of the viewer's eyes and the parallax allows the visual cortex to generate an depth perception, impression of depth. Optical design evolution Galilean Almost from the invention of the telescope in the 17th century the advantages of mounting two of them side by side for binocular vision seems to have been explored. Most early binoculars used Galilean telescope, Galilean optics; that is, they used a convex lens, convex objective (optics), objective and a concave lens, concave eyepi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orientation (geometry)
In geometry, the orientation, attitude, bearing, direction, or angular position of an object – such as a Line (geometry), line, plane (geometry), plane or rigid body – is part of the description of how it is placed in the Euclidean space, space it occupies. More specifically, it refers to the imaginary rotation that is needed to move the object from a reference placement to its current placement. A rotation may not be enough to reach the current placement, in which case it may be necessary to add an imaginary translation (geometry), translation to change the object's position (geometry), position (or linear position). The position and orientation together fully describe how the object is placed in space. The above-mentioned imaginary rotation and translation may be thought to occur in any order, as the orientation of an object does not change when it translates, and its position does not change when it rotates. Euler's rotation theorem shows that in three dimensions any orien ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hiking Equipment
Hiking equipment is the equipment taken on outdoor walking trips. The duration, distance, planned activities, and environment impacts equipment selection. For example, a short day hike across flat farmland versus trekking in the Himalayas would call for different types of equipment. Planning According to Tom Brown, the order of survival is shelter (including clothing), water, fire, and food. Cody Lundin writes about the "Rule of 3s" and states three minutes without air, three hours without shelter, three days without water, or three weeks without food will result in not surviving. Considerations for selecting hiking equipment: * Length and remoteness of trip * Weight hiker can carry * Capacity of equipment * Medical needs * Weather (e.g., temperature range, sun/shade, rain, snow, ice) * Terrain (e.g., trail conditions, cliffs, sand, swamp, river crossings) * Shelter * Clothes * Water * Food * Protection from animals (e.g., insect repellent, mace, bear spray, bear-r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Navigational Equipment
Navigation is a field of study that focuses on the process of monitoring and controlling the movement of a craft or vehicle from one place to another.Bowditch, 2003:799. The field of navigation includes four general categories: land navigation, marine navigation, aeronautic navigation, and space navigation. It is also the term of art used for the specialized knowledge used by navigators to perform navigation tasks. All navigational techniques involve locating the navigator's position compared to known locations or patterns. Navigation, in a broader sense, can refer to any skill or study that involves the determination of position and direction. In this sense, navigation includes orienteering and pedestrian navigation. For marine navigation, this involves the safe movement of ships, boats and other nautical craft either on or underneath the water using positions from navigation equipment with appropriate nautical charts (electronic and paper). Navigation equipment for ships is ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Forest Modelling
A forest is an ecosystem characterized by a dense community of trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations' Food and Agriculture Organization (FAO) defines a forest as, "Land spanning more than 0.5 hectares with trees higher than 5 meters and a canopy cover of more than 10 percent, or trees able to reach these thresholds ''in situ''. It does not include land that is predominantly under agricultural or urban use." Using this definition, '' Global Forest Resources Assessment 2020'' found that forests covered , or approximately 31 percent of the world's land area in 2020. Forests are the largest terrestrial ecosystems of Earth by area, and are found around the globe. 45 percent of forest land is in the tropical latitudes. The next largest share of forests are found in subarctic climates, followed by temperate, and subtropic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Qibla Compass
A qibla (qiblah) compass (sometimes also called qibla/qiblah indicator or ''qiblanuma'') is a modified compass used by Muslims to indicate the direction to face to perform prayers. In Islam, this direction is called qibla, and points towards the city of Mecca and specifically to the Kaaba. While the compass, like any other compass, points north, the direction of prayer is indicated by marks on the perimeter of the dial, corresponding to different cities, or by a second pointer set by the user according to their own location. To determine the proper direction, one has to know with some precision both the longitude and latitude of one's own location and those of Mecca, the city toward which one must face. Once that is determined, the values are applied to a spherical triangle, and the angle from the local meridian to the required direction of Mecca can be determined. The indicator usually consists of a round brass box with a hinged lid and an inset magnetic compass. A list of impo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prismatic Compass
A prismatic compass is a navigation and surveying instrument which is extensively used to find out the bearing of the traversing and included angles between them, waypoints (an endpoint of the course) and direction. Compass surveying is a type of surveying in which the directions of surveying lines are determined with a magnetic compass, and the length of the surveying lines are measured with a tape or chain or laser range finder A rangefinder (also rangefinding telemeter, depending on the context) is a device used to measure distances to remote objects. Originally optical devices used in surveying, they soon found applications in other fields, such as photography, t .... The compass is generally used to run a traverse line. The compass calculates bearings of lines with respect to magnetic needle. The included angles can then be calculated using suitable formulas in case of clockwise and anti-clockwise traverse respectively. For each survey line in the traverse, surveyors ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marine Sandglass
A marine sandglass is a timepiece of simple design that is a relative of the common hourglass, a marine (nautical) instrument known since the 14th century (although reasonably presumed to be of very ancient use and origin). Sandglasses were used to measure the time at sea or on a given navigational course, in repeated measures of small time increments (e.g., 30 minutes). Used together with the chip log, smaller marine sandglasses were also used to measure the boat speed through the water in knots. Although vital to maritime navigation, marine sandglasses were not accurate measuring instruments for the passage of time; many design and environmental factors could affect the duration of sand's flow, and therefore its reported time. Their use continued through the early 19th century, when they were supplanted by reliable mechanical timepieces and by other advances in marine navigation. Marine sandglasses were very popular on ships, as they were the most dependable measurement of tim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
History Of The Compass
The compass is a magnetometer used for navigation and orientation that shows direction in regards to the Cardinal direction, geographic cardinal points. The structure of a compass consists of the compass rose, which displays the four main directions on it: East (E), South (S), West (W) and North (N). The angle increases in the clockwise position. North corresponds to 0°, so east is 90°, south is 180° and west is 270°. The history of the compass started more than 2000 years ago during the Han dynasty (202 BC – 220 AD). The first compasses were made of lodestone, a naturally magnetized stone of iron, in Han dynasty China. It was called the "South Pointing Fish" and was used for land navigation by the mid-11th century during the Song dynasty (960–1279 AD). Shen Kuo provided the first explicit description of a magnetized needle in 1088 and Zhu Yu (author), Zhu Yu mentioned its use in maritime navigation in the text ''Pingzhou Table Talks'', dated 1111–1117. Later compasses w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grid Compass
The Grid Compass is a family of laptop computers introduced in 1982 by the Grid Systems Corporation. The design for the Compass was rendered by Bill Moggridge. Owing to its clamshell design—the first in a portable computer—some historians credit the original Compass as the first ever laptop. This original model of Compass lacked an internal battery compartment, requiring AC power from the wall. Grid sold the succeeding model, the Compass II, in 1984 with an optional external battery unit. Grid replaced the Compass with the GridCase line in 1985. History Development of the Compass began in 1979, and the main buyer was the U.S. government. NASA used it on the Space Shuttle during the early 1980s, as it was powerful, lightweight, and compact. The military Special Forces also purchased the machine, as it could be used by paratroopers in combat. The National Security Agency was reportedly interested in a TEMPEST-compliant version produced by SAIC. Along with the Gavilan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geological Compass
There are a number of different specialized magnetic compasses used by geologists to measure orientation of geological structures, as they map in the field, to analyze and document the geometry of bedding planes, joints, and/or metamorphic foliations and lineations. In this aspect the most common device used to date is the analogue compass. Classic geological compasses Classic geological compasses that are of practical use combine two functions, direction finding and navigation (especially in remote areas), and the ability to measure strike and dip of bedding surfaces and/or metamorphic foliation planes. Structural geologists (i.e. those concerned with geometry and the pattern of relative movement) also have a need to measure the plunge and plunge direction of lineations. Compasses in common use include the Brunton compass and the Silva compass. Modern geological compasses File:FPM compass with annotation en.svg, Setup of a modern geological compass after Prof. Clar (F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
