Synonyms containing chart datum

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Chart datum

Chart datum

A chart datum is the level of water that charted depths displayed on a nautical chart are measured from. A chart datum is generally a tidal datum; that is, a datum derived from some phase of the tide. Common chart datums are lowest astronomical tide and mean lower low water. The Chart Datum always refers to the date at which the soundings were taken regardless of method. Thus all NOAA charts, say in the SE United States, will indicate "North American Datum 1983". This is of great importance where tidal current or meteorological events like hurricanes, can and will change the depth contour. This is also of great importance where the Chart Datum was collected more than fifty years prior, as for example in the Bahamas or in Cuba and has not since been updated, verified, or sounded electronically. Chart datums achieved via dragging of chains adversely impacted the ecosystem and were rarely executed over sensitive bottoms, say coral reefs. Thus an older Datum will often be purposefully incorrect. They also relied on optical triangulation from fixed land points, and thus if taken over the horizon, fixes were taken from floating objects and are not necessarily correct. Lat/Longs determined via Satellite of land masses can be off by as much as 90ft in the Bahamas, Caribbean and Cuba. Datum is also the latin word for given, thus, "It is given that in 1984 the depth contour is such" does not indicate that in 2014 the depth contour is as indicated. Chart Datums boxes on paper charts will also usually indicate "updates" from the issuing organization, "corrections" to official charts by the publisher, and suppliers of electronic charts will also provide their own "corrections" that deviate from data 'given' from official charts. GPS receivers also provide offsets to reconcile the Datum to satellite triangulation. Where the chart indicates "Entry by visual navigation only", it must be assumed that the bottom contour is not 'given'.

— Freebase

Geodetic datum

Geodetic datum

A geodetic datum or geodetic system (also: geodetic reference datum or geodetic reference system) is a coordinate system, and a set of reference points, used for locating places on the Earth (or similar objects). An approximate definition of sea level is the datum WGS 84, an ellipsoid, whereas a more accurate definition is Earth Gravitational Model 2008 (EGM2008), using at least 2,159 spherical harmonics. Other datums are defined for other areas or at other times; ED50 was defined in 1950 over Europe and differs from WGS 84 by a few hundred meters depending on where in Europe you look. Mars has no oceans and so no sea level, but at least two martian datums have been used to locate places there. Datums are used in geodesy, navigation, and surveying by cartographers and satellite navigation systems to translate positions indicated on maps (paper or digital) to their real position on Earth. Each starts with an ellipsoid (stretched sphere), and then defines latitude, longitude and altitude coordinates. One or more locations on the Earth's surface are chosen as anchor "base-points". The difference in co-ordinates between datums is commonly referred to as datum shift. The datum shift between two particular datums can vary from one place to another within one country or region, and can be anything from zero to hundreds of meters (or several kilometers for some remote islands). The North Pole, South Pole and Equator will be in different positions on different datums, so True North will be slightly different. Different datums use different interpolations for the precise shape and size of the Earth (reference ellipsoids). Because the Earth is an imperfect ellipsoid, localised datums can give a more accurate representation of the area of coverage than WGS 84. OSGB36, for example, is a better approximation to the geoid covering the British Isles than the global WGS 84 ellipsoid. However, as the benefits of a global system outweigh the greater accuracy, the global WGS 84 datum is becoming increasingly adopted.Horizontal datums are used for describing a point on the Earth's surface, in latitude and longitude or another coordinate system. Vertical datums measure elevations or depths.

— Wikipedia

Chart

Chart

A chart is a graphical representation of data, in which "the data is represented by symbols, such as bars in a bar chart, lines in a line chart, or slices in a pie chart". A chart can represent tabular numeric data, functions or some kinds of qualitative structure and provides different info The term "chart" as a graphical representation of data has multiple meanings: ⁕A data chart is a type of diagram or graph, that organizes and represents a set of numerical or qualitative data. ⁕Maps that are adorned with extra information for some specific purpose are often known as charts, such as a nautical chart or aeronautical chart. ⁕Other domain specific constructs are sometimes called charts, such as the chord chart in music notation or a record chart for album popularity. Charts are often used to ease understanding of large quantities of data and the relationships between parts of the data. Charts can usually be read more quickly than the raw data that they are produced from. They are used in a wide variety of fields, and can be created by hand or by computer using a charting application. Certain types of charts are more useful for presenting a given data set than others. For example, data that presents percentages in different groups are often displayed in a pie chart, but may be more easily understood when presented in a horizontal bar chart. On the other hand, data that represents numbers that change over a period of time might be best shown as a line chart.

— Freebase

Position Finder

Position Finder

An instrument for determining the position of objects which are to be fired at from forts. It is designed for use from forts situated on the water.

Fiske's position finder may be thus generally described. On a chart the channel is divided into squares, and the position finder determines the square in which a vessel lies. For each square the direction and elevation of the guns is calculated beforehand. The enemy can therefore be continuously located and fired at, although from smoke or other cause the object may be quite invisible to the gunner.

It comprises two telescopes situated at distant extremities of as long a base line as is obtainable. These telescopes are kept directed upon the object by two observers simultaneously. The observers are in constant telephonic communication. As each telescope moves, it carries a contact over an arc of conducting material. Below each telescope is an arm also moving over an arc of conducting material. These arcs enter into a Wheatstone bridge and are so connected that when the arm and the distant telescope are at the same angle or parallel a balance is obtained. Thus each observer has the power of establishing a balance. A chart is provided for each of them, and over it the arm connected with the distant telescope and an arm or indicator attached to the telescope at that station move so that as long as both telescopes point at the object and each observer maintains the electric balance, the intersection of the arms shows the position on the chart.

The Position Finder is a simplification and amplification of the Range Finder, q. v. In practice the observers may be placed far from the forts, and may telephone their observations thereto. It has been found accurate within one-third of one per cent.

— The Standard Electrical Dictionary

Chart

Chart

chärt, n. a marine or hydrographical map, exhibiting a portion of a sea or other water, with the islands, coasts of contiguous land, soundings, currents, &c: an outline-map, or a tabular statement giving information of any kind.—adjs. Chartā′ceous; Chart′less. [O. Fr. charte—L. charta, a paper.]

— Chambers 20th Century Dictionary

Charter

Charter

chärt′er, n. any formal writing in evidence of a grant, contract, or other transaction, conferring or confirming titles, rights, or privileges, or the like: the formal deed by which a sovereign guarantees the rights and privileges of his subjects, like the famous Mag′na Chart′a, signed by King John at Runnymede, 15th June 1215, or the Charte of Louis XVIII. at the Restoration in 1814, or that sworn by Louis-Philippe, 29th August 1830: any instrument by which powers and privileges are conferred by the state on a select body of persons for a special object, as the 'charter of a bank:' a patent: grant, allowance: immunity.—v.t. to establish by charter: to let or hire, as a ship, on contract.—p.adj. Chart′ered, granted or protected by a charter: privileged: licensed: hired by contract. [O. Fr. chartre—L. cartula, carta.]

— Chambers 20th Century Dictionary

Height gauge

Height gauge

A height gauge is a measuring device used for determining the height of objects, and for marking of items to be worked on. These measuring tools are used in metalworking or metrology to either set or measure vertical distances; the pointer is sharpened to allow it to act as a scriber and assist in marking out work pieces. Devices similar in concept, with lower resolutions, are used in health care settings (health clinics, surgeries) to find the height of people, in which context they are called stadiometers. Height gauges may also be used to measure the height of an object by using the underside of the scriber as the datum. The datum may be permanently fixed or the height gauge may have provision to adjust the scale, this is done by sliding the scale vertically along the body of the height gauge by turning a fine feed screw at the top of the gauge; then with the scriber set to the same level as the base, the scale can be matched to it. This adjustment allows different scribers or probes to be used, as well as adjusting for any errors in a damaged or resharpened probe. In the toolroom, the distinction between a height gauge and a surface gauge is that a height gauge has a measuring head (whether vernier, fine rack and pinion with dial, or linear encoder with digital display), whereas a surface gauge has only a scriber point. Both are typically used on a surface plate and have a heavy base with an accurately flat, smooth underside.

— Wikipedia

ED50

ED50

ED50 ("European Datum 1950") is a geodetic datum which was defined after World War II for the international connection of geodetic networks.

— Wikipedia

westing

westing

A distance west of a datum line on a map or chart

— Wiktionary

Date

Date

dāt, n. the time of any event: a stipulated time: age, period of time.—v.t. to affix the date to.—v.t. to reckon: to begin.—adj. Date′less, without date: without fixed limit: undatable.—Out of date, antiquated; Up to date, adapted or corrected to the present time: modern. [O. Fr. date—L. datum, as in datum Romæ = given or written at Rome.]

— Chambers 20th Century Dictionary

Maren Morris

Maren Morris

Maren Larae Morris (born April 10, 1990) is an American singer, songwriter, and record producer. She has released two studio albums. Her 2015 extended play, Maren Morris, charted on two Billboard charts. Her major label debut album, Hero, reached number five on the Billboard 200 chart and number one on the Top Country Albums chart, and was certified platinum in the United States. Morris is also a member of The Highwomen, a group also consisting of Brandi Carlile, Amanda Shires and Natalie Hemby. Her first album Walk On was released in 2005. Her debut single, "My Church", peaked at number one on the Country Digital Songs chart in 2016 and reached the top five on the US Hot Country Songs chart and won a Grammy Award for Best Country Solo Performance. Her third single, "I Could Use a Love Song", was her first to reach number one on the US Country Airplay chart. She provided vocals for "The Middle", a pop collaboration with Zedd and Grey, released in January 2018, which reached number five on the Billboard Hot 100 and received three nominations at the 61st Grammy Awards. Morris' second album, Girl, was released on March 8, 2019, through Columbia Nashville, preceded by the lead single and title track. The album once again attained the top spot on the Top County Albums chart and peaked at number four on the Billboard 200 chart, while Morris achieved her first top 15 entry on the Billboard Hot 100 chart with the album's single "The Bones", which peaked at number 12.

— Wikipedia

Altitude

Altitude

Altitude or height is defined based on the context in which it is used. As a general definition, altitude is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point or object. The reference datum also often varies according to the context. Although the term altitude is commonly used to mean the height above sea level of a location, in geography the term elevation is often preferred for this usage. Vertical distance measurements in the "down" direction are commonly referred to as depth.

— Freebase

Moving average

Moving average

In statistics, a moving average, also called rolling average, moving mean, rolling mean, or running average, is a type of FIR filter used to analyze a set of data points by creating a series of averages of different subsets of the full data set. Given a series of numbers and a fixed subset size, the first element of the moving average is obtained by taking the average of the initial fixed subset of the number series. Then the subset is modified by "shifting forward"; that is, excluding the first number of the series and including the next number following the original subset in the series. This creates a new subset of numbers, which is averaged. This process is repeated over the entire data series. The plot line connecting all the averages is the moving average. A moving average is a set of numbers, each of which is the average of the corresponding subset of a larger set of datum points. A moving average may also use unequal weights for each datum value in the subset to emphasize particular values in the subset. A moving average is commonly used with time series data to smooth out short-term fluctuations and highlight longer-term trends or cycles. The threshold between short-term and long-term depends on the application, and the parameters of the moving average will be set accordingly. For example, it is often used in technical analysis of financial data, like stock prices, returns or trading volumes. It is also used in economics to examine gross domestic product, employment or other macroeconomic time series. Mathematically, a moving average is a type of convolution and so it can be viewed as an example of a low-pass filter used in signal processing. When used with non-time series data, a moving average filters higher frequency components without any specific connection to time, although typically some kind of ordering is implied. Viewed simplistically it can be regarded as smoothing the data.

— Freebase

Fourteener

Fourteener

In mountaineering terminology in the United States, a fourteener is a mountain that exceeds 14,000 feet above mean sea level. The importance of fourteeners is greatest in Colorado, which has the majority of such peaks in North America. Climbing all of Colorado's fourteeners is a popular pastime among peak baggers; another popular target is climbing all of the fourteeners in the contiguous United States. Various ski mountaineers have completed ski descents of all the Colorado fourteeners, and the first attempts are being made to complete ski descents of all U.S. fourteeners. Topographic elevation is the vertical distance above the reference geoid, a precise mathematical model of the Earth's sea level as an equipotential gravitational surface. Topographic prominence is the elevation difference between the summit and the highest or key col to a higher summit. Topographic isolation is the minimum great circle distance to a point of higher elevation. All elevations in the 48 states of the contiguous United States include an elevation adjustment from the National Geodetic Vertical Datum of 1929 to the North American Vertical Datum of 1988. If a summit elevation or prominence has a range of values, the arithmetic mean is cited.

— Freebase

Centring

Centring

Centring, or centering, is the structure upon which the stones of arches or vault are laid during construction. Once the arch is complete, it supports itself, but until the keystone is inserted, it has no strength and needs the centring to keep the voussoirs in their correct relative positions. The centring is normally made of wood, which was a relatively straightforward structure in a simple arch or vault, but with more complex shapes, involving double curvature, such as a small dome or the bottle-shaped flues of the kitchens of some Norman-period houses; clay or sand bound by a weak lime mortar mix could be used. The shaping of this sort of centring would probably be done by eye, perhaps with the help of a template and the stone or brick structure laid against it. On bigger work, like a 19th-century commercial pottery kiln, this was impractical. The structure would be built round a post acting as a datum, and each course of stonework would be set at a distance from the datum as measured by a stick or string. On completion of the intended structure, the centring of whichever sort is removed, and work on pointing and other finishing continued.

— Freebase

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Quiz

Are you a human thesaurus?

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Which of the following words is not a synonym of the others?
  • A. adversary
  • B. opposer
  • C. opponent
  • D. protagonist