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Topic Review
True Range Multilateration
True range multilateration is a method to determine the location of a movable vehicle or stationary point in space using multiple ranges (distances) between the vehicle/point and multiple spatially-separated known locations (often termed 'stations'). True range multilateration is both a mathematical topic and an applied technique used in several fields. A practical application involving a fixed location is the trilateration method of surveying. Applications involving vehicle location are termed navigation when on-board persons/equipment are informed of its location, and are termed surveillance when off-vehicle entities are informed of the vehicle's location. Two slant-ranges from two known locations can be used to locate a third point in a two-dimensional Cartesian space (plane), which is a frequently applied technique (e.g., in surveying). Similarly, two spherical ranges can be used to locate a point on a sphere, which is a fundamental concept of the ancient discipline of celestial navigation — termed the altitude intercept problem. Moreover, if more than the minimum number of ranges are available, it is good practice to utilize those as well. This article addresses the general issue of position determination using multiple ranges. In two-dimensional geometry, it is known that if a point lies on two circles, then the circle centers and the two radii provide sufficient information to narrow the possible locations down to two – one of which is the desired solution and the other is an ambiguous solution. Additional information often narrow the possibilities down to a unique location. In three-dimensional geometry, when it is known that a point lies on the surfaces of three spheres, then the centers of the three spheres along with their radii also provide sufficient information to narrow the possible locations down to no more than two (unless the centers lie on a straight line). True range multilateration can be contrasted to the more frequently encountered (pseudorange) multilateration, which employs range differences to locate a (typically, movable) point. Pseudo range multilateration is almost always implemented by measuring times-of-arrival (TOAs) of energy waves. True range multilateration can also be contrasted to triangulation, which involves the measurement of angles. Multiple, sometimes overlapping and conflicting terms are employed for similar concepts – e.g., multilateration without modification has been used for aviation systems employing both true ranges and pseudo ranges. Moreover, different fields of endeavor may employ different terms. In geometry, trilateration is defined as the process of determining absolute or relative locations of points by measurement of distances, using the geometry of circles, spheres or triangles. In surveying, trilateration is a specific technique. The term true range multilateration is accurate, general and unambiguous. Authors have also used the terms range-range and rho-rho multilateration for this concept.
  • 742
  • 25 Oct 2022
Topic Review
Bryce Canyon National Park
Bryce Canyon National Park (/braɪs/) is an American national park located in southwestern Utah. The major feature of the park is Bryce Canyon, which despite its name, is not a canyon, but a collection of giant natural amphitheaters along the eastern side of the Paunsaugunt Plateau. Bryce is distinctive due to geological structures called hoodoos, formed by frost weathering and stream erosion of the river and lake bed sedimentary rocks. The red, orange, and white colors of the rocks provide spectacular views for park visitors. Bryce Canyon National Park is much smaller, and sits at a much higher elevation than nearby Zion National Park. The rim at Bryce varies from 8,000 to 9,000 feet (2,400 to 2,700 m). The Bryce Canyon area was settled by Mormon pioneers in the 1850s and was named after Ebenezer Bryce, who homesteaded in the area in 1874. The area around Bryce Canyon was originally designated as a national monument by President Warren G. Harding in 1923 and was redesignated as a national park by Congress in 1928. The park covers 35,835 acres (55.992 sq mi; 14,502 ha; 145.02 km2) and receives substantially fewer visitors than Zion National Park (nearly 4.3 million in 2016) or Grand Canyon National Park (nearly 6 million in 2016), largely due to Bryce's more remote location. In 2016, Bryce Canyon received 2,365,110 recreational visitors, representing an increase of 35% from the prior year.
  • 480
  • 25 Oct 2022
Topic Review
Alcohol Belts of Europe
The alcohol belts of Europe divide Europe by their traditional alcoholic beverages: beer, wine, or spirits. They do not necessarily correspond with current drinking habits, as beer has become the most popular alcoholic drink world-wide. The definitions of these belts are not completely objective.
  • 889
  • 25 Oct 2022
Topic Review
Lake Rotoma
Lake Rotoma is the fourth largest lake of the 11 lakes in the Rotorua Lakes district, or the Hot Lakes district as it was known in the early decades of the 20th century. The Rotorua lakes are located in New Zealand's North Island in the Bay of Plenty Region. Lake Rotoma is the easternmost in the chain of three lakes to the northeast of Lake Rotorua The other two are Lake Rotoiti and Lake Rotoehu. Rotoma is located halfway between the city of Rotorua and town of Whakatane. Lake Rotoma has a high water quality with visibility up to around 13 metres deep. The lake has a maximum depth of 83 metres in the northern part and 73.5 metres in the southern part.
  • 821
  • 24 Oct 2022
Topic Review
Hunga Tonga
Template:Infobox Island Hunga Tonga-Hunga Haʻapai is a volcanic island located about 30 kilometres (19 miles) south-southeast of Fonuafoʻou island in Tonga. The volcano is part of the highly active Tonga-Kermadec Islands volcanic arc, a subduction zone extending from New Zealand north-northeast to Fiji. It lies about 100 kilometres (62 mi) above a very active seismic zone. The island arc is formed at the convergent boundary where the Pacific Plate subducts under the Indo-Australian Plate.
  • 1.5K
  • 24 Oct 2022
Topic Review
Taupo Volcanic Zone
The Taupō Volcanic Zone (TVZ) is a volcanic area in the North Island of New Zealand that has been active for the past two million years and is still highly active. Mount Ruapehu marks its south-western end and the zone runs north-eastward through the Taupo and Rotorua areas and offshore into the Bay of Plenty. It is part of the larger Central Volcanic Region that extends further westward through the western Bay of Plenty to the eastern side of the Coromandel Peninsula and has been active for four million years. The Taupo Volcanic Zone is widening east–west at the rate of about 8 mm per year. It is named after Lake Taupo, the flooded caldera of the largest volcano in the zone, the Taupo Volcano.
  • 869
  • 24 Oct 2022
Topic Review
Page LaPyout (Cartography)
Page layout, also called map layout or map composition, is the part of Cartographic design that involves assembling various map elements on a page. This may include the map image itself, along with titles, legends, scale indicators, inset maps, and other elements. It follows principles similar to page layout in graphic design, such as balance, gestalt, and visual hierarchy. The term map composition is also used for the assembling of features and symbols within the map image itself, which can cause some confusion; these two processes share a few common design principles but are distinct procedures in practice. Similar principles of layout design apply to maps produced in a variety of media, from large format wall maps to illustrations in books to interactive web maps, although each medium has unique constraints and opportunities.
  • 474
  • 24 Oct 2022
Topic Review
Locative Media
Locative media or location-based media (LBM) are media of communication functionally bound to a location. The physical implementation of locative media, however, is not bound to the same location to which the content refers. Location-based media delivers multimedia and other content directly to the user of a mobile device dependent upon their location. Location information determined by means such as mobile phone tracking and other emerging real-time locating system technologies like Wi-Fi or RFID can be used to customize media content presented on the device. Locative media are digital media applied to real places and thus triggering real social interactions. While mobile technologies such as the Global Positioning System (GPS), laptop computers and mobile phones enable locative media, they are not the goal for the development of projects in this field.
  • 1.3K
  • 24 Oct 2022
Topic Review
Ayat Al-Akhras
Ayat al-Akhras (February 20, 1985 – March 29, 2002) was the third and youngest Palestinian female suicide bomber who, at age 18 (some sources report her age to be as young as 16), killed herself and two Israeli civilians on March 29, 2002 by detonating explosives belted to her body. The killings gained widespread international attention due to Ayat's age and gender and the fact that one of the victims was also a teenage girl. The killings led U.S. President George W. Bush to observe: “When an 18-year-old Palestinian girl is induced to blow herself up and in the process kills a 17-year-old Israeli girl, the future itself is dying; the future of the Palestinian people and the future of the Israeli people.”
  • 754
  • 24 Oct 2022
Topic Review
Coppermine Expedition of 1819–22
The Coppermine Expedition of 1819–1822 had as its goal the exploration of the northern coast of Canada , which was accessed by way of the Coppermine River. The British expedition was organised by the Royal Navy as part of its attempt to discover and map the Northwest Passage. It was the first of three Arctic expeditions to be led by John Franklin, and also included George Back and Dr. John Richardson, both of whom would become notable Arctic explorers in their own right. The expedition was plagued by poor planning, bad luck and unreliable allies. The expected assistance from the local fur trading companies and native peoples was less forthcoming than expected, and the dysfunctional supply line, coupled with unusually harsh weather and the resulting absence of game, meant that the explorers were never far from starvation. Eventually the Arctic coast was reached, but barely 500 mi (800 km) had been explored before the exhaustion of the party's supplies and the onset of winter forced it to turn back. The expedition made a desperate retreat across uncharted territory in a state of starvation, often with nothing more than lichen to eat. Eleven of the twenty-strong party died amid accusations of murder and cannibalism before the survivors were rescued by people of the Yellowknives First Nation, who had previously given them up for dead. In the aftermath of the expedition, Franklin was much criticised by local fur traders for his haphazard planning and failure to adapt to the circumstances he faced, but in Britain he was received as a hero, and fêted for the courage he had shown in extreme adversity. The expedition captured the public imagination, and in reference to a desperate measure he took while starving, he became known as "the man who ate his boots".
  • 427
  • 24 Oct 2022
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