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Linear Scale
A linear scale, also called a bar scale, scale bar, graphic scale, or graphical scale, is a means of visually showing the scale of a map, nautical chart, engineering drawing, or architectural drawing. A scale bar is common element of map layouts. On large scale maps and charts, those covering a small area, and engineering and architectural drawings, the linear scale can be very simple, a line marked at intervals to show the distance on the earth or object which the distance on the scale represents. A person using the map can use a pair of dividers (or, less precisely, two fingers) to measure a distance by comparing it to the linear scale. The length of the line on the linear scale is equal to the distance represented on the earth multiplied by the map or chart's scale. In most projections, scale varies with latitude, so on small scale maps, covering large areas and a wide range of latitudes, the linear scale must show the scale for the range of latitudes covered by the map. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equator
The equator is a circle of latitude, about in circumference, that divides Earth into the Northern and Southern hemispheres. It is an imaginary line located at 0 degrees latitude, halfway between the North and South poles. The term can also be used for any other celestial body that is roughly spherical. In spatial (3D) geometry, as applied in astronomy, the equator of a rotating spheroid (such as a planet) is the parallel (circle of latitude) at which latitude is defined to be 0°. It is an imaginary line on the spheroid, equidistant from its poles, dividing it into northern and southern hemispheres. In other words, it is the intersection of the spheroid with the plane perpendicular to its axis of rotation and midway between its geographical poles. On and near the equator (on Earth), noontime sunlight appears almost directly overhead (no more than about 23° from the zenith) every day, year-round. Consequently, the equator has a rather stable daytime temperature throu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cartography
Cartography (; from grc, χάρτης , "papyrus, sheet of paper, map"; and , "write") is the study and practice of making and using maps. Combining science, aesthetics and technique, cartography builds on the premise that reality (or an imagined reality) can be modeled in ways that communicate spatial information effectively. The fundamental objectives of traditional cartography are to: * Set the map's agenda and select traits of the object to be mapped. This is the concern of map editing. Traits may be physical, such as roads or land masses, or may be abstract, such as toponyms or political boundaries. * Represent the terrain of the mapped object on flat media. This is the concern of map projections. * Eliminate characteristics of the mapped object that are not relevant to the map's purpose. This is the concern of generalization. * Reduce the complexity of the characteristics that will be mapped. This is also the concern of generalization. * Orchestrate the elements of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Cartographic Association
The International Cartographic Association (ICA) (french: Association Cartographique Internationale, ''ACI''), is an organization formed of national member organizations, to provide a forum for issues and techniques in cartography and geographic information science (GIScience). ICA was founded on June 9, 1959, in Bern, Switzerland. The first General Assembly was held in Paris in 1961. The mission of the International Cartographic Association is to promote the disciplines and professions of cartography and GIScience in an international context. To achieve these aims, the ICA works with national and international governmental and commercial bodies, and with other international scientific societies. Leadership Presidents The first president, Eduard Imhof of Switzerland was heavily involved in founding the association. Secretaries-General and Treasurers The Secretary-General and Treasurer is responsible for the administration and the general running of the Association. Ex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Logarithmic Scale
A logarithmic scale (or log scale) is a way of displaying numerical data over a very wide range of values in a compact way—typically the largest numbers in the data are hundreds or even thousands of times larger than the smallest numbers. Such a scale is nonlinear: the numbers 10 and 20, and 60 and 70, are not the same distance apart on a log scale. Rather, the numbers 10 and 100, and 60 and 600 are equally spaced. Thus moving a unit of distance along the scale means the number has been ''multiplied'' by 10 (or some other fixed factor). Often exponential growth curves are displayed on a log scale, otherwise they would increase too quickly to fit within a small graph. Another way to think about it is that the ''number of digits'' of the data grows at a constant rate. For example, the numbers 10, 100, 1000, and 10000 are equally spaced on a log scale, because their numbers of digits is going up by 1 each time: 2, 3, 4, and 5 digits. In this way, adding two digits ''multiplies'' th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scale (map)
The scale of a map is the ratio of a distance on the map to the corresponding distance on the ground. This simple concept is complicated by the curvature of the Earth's surface, which forces scale to vary across a map. Because of this variation, the concept of scale becomes meaningful in two distinct ways. The first way is the ratio of the size of the generating globe to the size of the Earth. The generating globe is a conceptual model to which the Earth is shrunk and from which the map is projected. The ratio of the Earth's size to the generating globe's size is called the nominal scale (= principal scale = representative fraction). Many maps state the nominal scale and may even display a bar scale (sometimes merely called a 'scale') to represent it. The second distinct concept of scale applies to the variation in scale across a map. It is the ratio of the mapped point's scale to the nominal scale. In this case 'scale' means the scale factor (= point scale = particular scale) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
British Admiralty
The Admiralty was a department of the Government of the United Kingdom responsible for the command of the Royal Navy until 1964, historically under its titular head, the Lord High Admiral – one of the Great Officers of State. For much of its history, from the early 18th century until its abolition, the role of the Lord High Admiral was almost invariably put "in commission" and exercised by the Lords Commissioner of the Admiralty, who sat on the governing Board of Admiralty, rather than by a single person. The Admiralty was replaced by the Admiralty Board in 1964, as part of the reforms that created the Ministry of Defence and its Navy Department (later Navy Command). Before the Acts of Union 1707, the Office of the Admiralty and Marine Affairs administered the Royal Navy of the Kingdom of England, which merged with the Royal Scots Navy and the absorbed the responsibilities of the Lord High Admiral of the Kingdom of Scotland with the unification of the Kingdom of Gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Hydrographic Organization
The International Hydrographic Organization (IHO) is an intergovernmental organisation representing hydrography. , the IHO comprised 98 Member States. A principal aim of the IHO is to ensure that the world's seas, oceans and navigable waters are properly surveyed and charted. It does this through the setting of international standards, the co-ordination of the endeavours of the world's national hydrographic offices, and through its capacity building program. The IHO enjoys observer status at the United Nations, where it is the recognised competent authority on hydrographic surveying and nautical charting. When referring to hydrography and nautical charting in Conventions and similar Instruments, it is the IHO standards and specifications that are normally used. History The IHO was established in 1921 as the International Hydrographic Bureau (IHB). The present name was adopted in 1970, as part of a new international Convention on the IHO adopted by the then member nations. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bowditch's American Practical Navigator
''The American Practical Navigator'' (colloquially often referred to as ''Bowditch''), originally written by Nathaniel Bowditch, is an encyclopedia of navigation. It serves as a valuable handbook on oceanography and meteorology, and contains useful tables and a maritime glossary. In 1867 the copyright and plates were bought by the Hydrographic Office of the United States Navy. As of 2019 it is still published by the U.S. Government and is available free online from the National Geospatial-Intelligence Agency (NGA), the modern successor agency to the 19th Century Hydrographic Office. The publication is considered one of America's nautical institutions. History The most popular navigational text of the late 18th century was ''The Practical Navigator'' by John Hamilton Moore of the Royal Navy, first published in 1772. To have exact tables to work from, Bowditch recomputed all of Moore's tables, and rearranged and expanded the work. He contacted the US publisher of the work, Edmu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
178 Central Street Somerville MA
Year 178 ( CLXXVIII) was a common year starting on Wednesday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Scipio and Rufus (or, less frequently, year 931 ''Ab urbe condita''). The denomination 178 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years. Events By place Roman Empire * Bruttia Crispina marries Commodus, and receives the title of '' Augusta''. * Emperor Marcus Aurelius and his son Commodus arrive at Carnuntum in Pannonia, and travel to the Danube to fight against the Marcomanni. Asia * Last (7th) year of ''Xiping'' era and start of ''Guanghe'' era of the Chinese Han Dynasty. * In India, the decline of the Kushan Empire begins. The Sassanides take over Central Asia. Religion * The Montanist heresy is condemned for the first time. Births * Lü Meng, Chinese general (d. 220) * Peng ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World Map
A world map is a map of most or all of the surface of Earth. World maps, because of their scale, must deal with the problem of projection. Maps rendered in two dimensions by necessity distort the display of the three-dimensional surface of the earth. While this is true of any map, these distortions reach extremes in a world map. Many techniques have been developed to present world maps that address diverse technical and aesthetic goals. Charting a world map requires global knowledge of the earth, its oceans, and its continents. From prehistory through the Middle ages, creating an accurate world map would have been impossible because less than half of Earth's coastlines and only a small fraction of its continental interiors were known to any culture. With exploration that began during the European Renaissance, knowledge of the Earth's surface accumulated rapidly, such that most of the world's coastlines had been mapped, at least roughly, by the mid-1700s and the continental in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
%2C_American_mathematician_and_actuary.jpeg "Click for more on -> Bowditch's American Practical Navigator")
