1.
Imperial system
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The Imperial Units replaced the Winchester Standards, which were from 1588 to 1825. The system came across the British Empire. The imperial system developed from what were first known as English units, as did the related system of United States customary units. The Weights and Measures Act of 1824 was initially scheduled to go on 1 May 1825. However, the Weights and Measures Act of 1825 pushed back the date to 1 January 1826. The 1824 Act allowed the continued use of pre-imperial units provided that they were widely known, clearly marked with imperial equivalents. Apothecaries' units are mentioned neither in the act of 1824 nor 1825. In Scotland, apothecaries' units were unofficially regulated by the Edinburgh College of Physicians. The three colleges published, at infrequent intervals, pharmacopoeiae, Dublin editions having the force of law. The Medical Act of 1858 transferred to The Crown the right to regulate apothecaries' weights and measures. Metric equivalents in this article usually assume the latest official definition. Before this date, the most precise measurement of the imperial Standard Yard was ♠ 0.914398416 metres. The Weights and Measures Act of 1985 switched to a gallon of exactly 6997454609000000000♠4.54609 l. These measurements were from 1826 when the new imperial gallon was defined, but were officially abolished in the United Kingdom on 1 January 1971. In the USA, though longer recommended, the apothecaries' system is still used occasionally in medicine, especially in prescriptions for older medications.
Imperial system
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The former Weights and Measures office in Seven Sisters, London.
Imperial system
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Imperial standards of length 1876 in Trafalgar Square, London.
Imperial system
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A baby bottle that measures in three measurement systems—metric, imperial (UK), and US customary.
Imperial system
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A one US gallon gas can purchased near the US-Canada border. It shows equivalences in imperial gallons and litres.
2.
US customary system
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United States customary units are a system of measurements commonly used in the United States. The United States customary system developed from English units which were in use in the British Empire before the US declared its independence. However, the British system of measures was overhauled in 1824 to create the imperial system, changing the definitions of some units. Therefore, while many U.S. units are essentially similar to their Imperial counterparts, there are significant differences between the systems. These definitions were refined by the international yard and agreement of 1959. Americans primarily use customary units in commercial activities, well as for personal and social use. In science, medicine, some of government, metric units are used. The modern form of the metric system, is preferred for many uses by the U.S. National Institute of Standards and Technology. The United States system of units is similar to the imperial system. The customary system was championed by Measures in the late 19th century. Advocates of the customary system saw the French metric, system as atheistic. An auxiliary of the Institute in Ohio published a poem with wording such as "down with every ` metric' scheme" and "a perfect pint". One adherent of the customary system called it "a just measure, which alone are acceptable to the Lord." The legislation states that the federal government has a responsibility to assist industry as it voluntarily converts to i.e. metrification. This is most evident in U.S. labeling requirements on food products, where SI units are almost always presented alongside customary units.
US customary system
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A 23.7 US fl oz (700 ml) bottle displaying both US and metric units.
3.
Area
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Area is the quantity that expresses the extent of a two-dimensional figure or shape, or planar lamina, in the plane. Surface area is its analog on the two-dimensional surface of a three-dimensional object. It is the two-dimensional analog of the volume of a solid. The area of a shape can be measured by comparing the shape to squares of a fixed size. A shape with an area of three square metres would have the same area as three such squares. In mathematics, the area of any other shape or surface is a dimensionless real number. There are well-known formulas for the areas of simple shapes such as triangles, rectangles, circles. Using these formulas, the area of any polygon can be found by dividing the polygon into triangles. For shapes with curved boundary, calculus is usually required to compute the area. Indeed, the problem of determining the area of plane figures was a major motivation for the historical development of calculus. For a solid shape such as a sphere, cylinder, the area of its boundary surface is called the surface area. Area plays an important role in modern mathematics. In analysis, the area of a subset of the plane is defined using Lebesgue measure, though not every subset is measurable. In general, area in higher mathematics is seen as a special case of volume for two-dimensional regions. It can be proved that such a function exists.
Area
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A square metre quadrat made of PVC pipe.
Area
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The combined area of these three shapes is approximately 15.57 squares.
4.
Square (geometry)
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In geometry, a square is a regular quadrilateral, which means that it has four equal sides and four equal angles. It can also be defined as a rectangle in which two adjacent sides have equal length. A square with vertices ABCD would be denoted ◻ ABCD. Opposite sides of a square are both equal in length. All four angles of a square are equal. All four sides of a square are equal. The diagonals of a square are equal. The square is the n = 2 case of the families of n-orthoplexes. A square has Schläfli symbol. T, is an octagon. H, is a digon. The area A is A = ℓ 2. In classical times, the second power was described in terms of the area of a square, as in the above formula. This led to the use of the square to mean raising to the second power. The area can also be calculated using the diagonal d according to A = d 2.
Square (geometry)
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A regular quadrilateral (tetragon)
5.
Mile
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This form of the mile then spread to the British-colonized nations who continue to employ the mile. Derived units such as miles per gallon, however, continue to be universally abbreviated as mph, mpg, so on. The English word mile derives from Middle English myl and Old English mīl, cognate with all other Germanic terms for "miles". The international mile is usually what is understood by the unqualified term "mile". When this distance needs to be distinguished from the nautical mile, the international mile may also be described as "statute mile". Under American law, however, the "mile" refers to the US survey mile. The mile has been variously abbreviated -- without a trailing period -- as m, M, ml, mi. The American National Institute of Standards and Technology now recommends mi in order to avoid confusion with the SI metre and millilitre. The BBC style holds that "There is no acceptable abbreviation for ‘miles’" and so it should be spelt out when used in describing areas. The ancient Romans, marching their armies through uncharted territory, would often push a carved stick in the ground after each 1000 paces. Well-fed and harshly driven Roman legionaries in good weather thus created longer miles. The distance was indirectly standardised by Agrippa's establishment of a standard Roman foot in the definition of a pace as 5 feet. An Imperial Roman mile thus denoted 5,000 Roman feet. Specialized equipment such as the decempeda and dioptra then spread its use. In modern times, Agrippa's Imperial Roman mile was empirically estimated to have been about 1,481 metres in length.
Mile
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A milestone in Westminster showing the distance from Knightsbridge to Hounslow and Hyde Park Corner in miles.
Mile
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The remains of the Golden Milestone, the zero mile marker of the Roman road network, in the Roman Forum.
Mile
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Edinburgh 's " Royal Mile "—running from the castle to Holyrood Abbey —is roughly a Scots mile long.
6.
Square foot
Square foot
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Comparison of 1 Square foot with some Imperial and metric units of area
7.
Square yard
Square yard
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Comparison of 1 Square yard with some Imperial and metric units of area
8.
Acre
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The acre is a unit of land area used in the imperial and US customary systems. The international symbol of the acre is ac. Today is the international acre. In the United States both the US survey acre are in use, but differ by only two parts per million, see below. The most common use of the acre is to measure tracts of land. One international acre is defined as exactly 4,046.8564224 square metres. An acre was defined in the Middle Ages, being the amount of land that could be ploughed with a yoke of oxen. One acre equals 0.0015625 square miles, 4,840 square yards, about 4,047 square metres. A square enclosing one acre is 208 feet 9 inches on a side. As a unit of measure, an acre has no prescribed shape; any area of 43,560 square feet is an acre. Consequently, the international acre is exactly 4,046.8564224 square metres. Surveyors in the United States use both international and survey feet, consequently, both varieties of acre. Areas are seldom measured with sufficient accuracy for the different definitions to be detectable. In India, residential plots are measured in cents or decimel, one hundredth of 435.60 square feet. In Sri Lanka the division of an acre into 4 roods is common.
Acre
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Comparison of 1 Acre with some Imperial and metric units of area
9.
Metric system
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The metric system is an internationally agreed decimal system of measurement. Many sources also cite Liberia and Myanmar as the other countries not to have done so. These base units are used to derive smaller units that could replace a huge number of other units of measure in existence. Although the system was first developed for commercial use, the development of coherent units of measure made it particularly suitable for engineering. Although the metric system has developed since its inception, its basic concepts have hardly changed. Designed for transnational use, it consisted of a basic set of units of measurement, now known as base units. At the outbreak of the French Revolution in 1789, even some cities had their own system of measurement. However, the custody of the metric system remained in the hands of the French government until 1875. In languages where the distinction is made, unit names are common nouns. The concept of using classical names for the prefixes was first proposed in a report by the Commission on Weights and Measures in May 1793. The prefix milli is to indicate a one-thousandth part of the unit. A milligram and millimetre are one thousandth of a gram and metre respectively. However, 1935 extensions to the system did not follow this convention: the prefixes nano - and micro -, for example have Greek roots. During the 19th century the prefix -, derived from the Greek word μύριοι, was used as a multiplier for 7004100000000000000 ♠ 10000. Prefixes are not usually used to indicate multiples of a second greater than 1; the non-SI units of minute, day are used instead.
Metric system
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"The metric system is for all people for all time." (Condorcet, 1791). Four everyday measuring devices that have metric calibrations: a tape measure calibrated in centimetres, a thermometer calibrated in degrees Celsius, a kilogram weight, and an electrical multimeter that measures volts, amperes and ohms.
Metric system
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Countries which have officially adopted the metric system
Metric system
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Chinese road sign listing distances on an expressway in eastern Beijing. Although the primary text is in Chinese, the distances use internationally recognised characters.
Metric system
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James Clerk Maxwell played a major role in developing the concept of a coherent CGS system and in extending the metric system to include electrical units.
10.
Square centimetre
Square centimetre
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Comparison of 1 Square metre with some Imperial and metric units of area
11.
Square metre
Square metre
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Comparison of 1 Square metre with some Imperial and metric units of area
12.
Hectare
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An acre is about 0.405 hectare and one hectare contains about 2.47 acres. In 1795, when the metric system was introduced, the "are" was defined as 100 square metres and the hectare was thus 100 "ares" or 1⁄100 km2. When the metric system was further rationalised in 1960, resulting in the International System of Units, the are was not included as a recognised unit. The metric system of measurement was first given a legal basis in 1795 by the French Revolutionary government. In 1960, when the metric system was updated as the International System of Units, the are did not receive international recognition. Many farmers, especially older ones, still use the acre for everyday calculations, convert to hectares only for official paperwork. The names hectare are derived by adding the metric prefixes to the original base unit of area, the are. The centiare is a synonym for one square metre. The deciare is ten square metres. The are is a unit of area, equal to 100 square metres, used for measuring land area. It was defined by older forms of the metric system, but is now outside of the modern International System of Units. It is commonly used to measure real estate, in particular in Indonesia, India, in French-, Portuguese-, Slovakian-, Serbian-, Czech-, Polish-, Dutch-, German-speaking countries. In Russia and other former Soviet Union states, the "sotka" is identical to the are. It is used to describe the size of suburban dacha or allotment garden plots or small city parks where the hectare would be too large. The decare is derived from deka, the prefix for 10 and are, is equal to 10 ares or 1000 square metres.
Hectare
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Trafalgar Square has an area of about one hectare.
Hectare
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Definition of a hectare and of an are.
Hectare
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Waikato Stadium – Hamilton, New Zealand
Hectare
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The Statue of Liberty – New York Harbor
13.
Square kilometre
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Square kilometre or square kilometer, symbol km², is a multiple of the square metre, the SI unit of area or surface area. For example, 3 km2 is equal to 3 2 = 3,000,000 m2, not 3,000 m2. Topographical map grids are worked out with the grid lines being 1,000 metres apart. For 1:50,000 maps, the grid lines are 2 cm apart. Each square on the map represents 1 km2 on the surface of the earth. For 1:25,000 maps, the grid lines are 4 cm apart. Each square on the map is 4 cm by 4 cm and represents 1 km2 on the surface of the earth. In each case, the grid lines enclose one square kilometre. The area enclosed by the walls of many medieval cities were about one square kilometre. The approximate area of the walled cities can often be worked out by fitting the course of the wall to a rectangle or an oval. Examples include Netherlands 52 ° 0 ′ 54 ″ N 4 ° 21 ′ 34 ″ E The walled city of Delft was approximately rectangular. The approximate length of rectangle was about 1.30 kilometres. The approximate width of the rectangle was about 0.75 kilometres. The maximum distance from east to west is 1.36 kilometres. The maximum distance from north to south is 0.80 kilometres.
Square kilometre
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Part of an Ordnance Survey map, published 1952. The grid lines are at one kilometre intervals giving each square an area of one square kilometre. The map shows that the area of the island is about two square kilometres.
Square kilometre
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Map of Delft, Netherlands dated 1659. The walls enclosed an area of about 1 square kilometre
14.
Section (United States land surveying)
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Sections are customarily surveyed into smaller squares by repeated halving and quartering. A quarter section is 160 acres and a "quarter-quarter section" is 40 acres. After the Civil War, Freedmen were reckoned to be self-sufficient with "40 acres and a mule." In the 20th century real estate developers preferred working with 40-acre parcels. The phrases "front 40" and "back 40," referring to farm fields, indicate the front and back quarter-quarter sections of land. A section can be halved seven times in this way, down to a 5-acre parcel, or half of a quarter-quarter-quarter section—an easily surveyed 50-square-chain area. This system was of great practical value on the American frontier, where surveyors often had a shaky grasp of mathematics and were required to work quickly. A description of a quarter-quarter section in standard abbreviated form, might look like "NW 1/4, NE 1/4, Sec. 34, T.3S, R.1W, 1st P.M.". In expanded form this would read "the Northwest quarter of the Northeast quarter of Section 34 of Township 3 South, Range 1 West, first Principal Meridian". The existence of section lines made property descriptions far more straightforward than the old metes and bounds system. This law provided that lands outside the then-existing states could not be sold, otherwise distributed, or opened for settlement prior to being surveyed. The standard way of doing this was to divide the land into sections. An area six sections by six sections would define a township. Within this area, one section was designated as school land. Every township is divided into 36 sections, each usually 1 mile square.
Section (United States land surveying)
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Perfectly square full sections of farmland cover Central Indiana.
Section (United States land surveying)
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Sectioning a township (36 sections).
Section (United States land surveying)
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Satellite image of crops growing in Kansas, mainly using center pivot irrigation. The primary grid pattern is of quarter sections (1 ⁄ 2 mi × 1 ⁄ 2 mi (800 m × 800 m)).
Section (United States land surveying)
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A brass disc in concrete marking a quarter section corner.
15.
University of North Carolina at Chapel Hill
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The public institution of higher education in the school opened its doors on February 1795. The university offers degrees in over 70 courses of study through fourteen colleges and the College of Arts and Sciences. In 1952, North Carolina opened its own hospital, UNC Health Care, for research and treatment, has since specialized in cancer care. The school's students, alumni, sports teams are known as "Tar Heels". The campus covers 729 acres of Chapel Hill's downtown area, encompassing the Morehead Planetarium and the many stores and shops located on Franklin Street. Students can participate in over 550 officially recognized student organizations. North Carolina is one of the charter members of the Atlantic Coast Conference, founded on June 14, 1953. Competing athletically as North Carolina has achieved great success in sports, most notably in women's hockey. In 1955, UNC Chapel Hill officially desegregated its undergraduate divisions. During the 1960s, the campus was the location of significant political protest. The climate of civil unrest prompted the 1963 Speaker Ban Law prohibiting speeches by communists on state campuses in North Carolina. From the late 1990s and onward, UNC Chapel Hill expanded rapidly with a 15% increase in total student population to more than 28,000 by 2007. Professor Oliver Smithies was awarded the Nobel Prize in Medicine in 2007 for his work in genetics. Additionally, Aziz Sancar was awarded the Nobel Prize in Chemistry in 2015 for his work in understanding the molecular repair mechanisms of DNA. The current chancellor is Carol Folt, the first woman to hold the post.
University of North Carolina at Chapel Hill
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University of North Carolina course catalog from June 1819
University of North Carolina at Chapel Hill
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University of North Carolina at Chapel Hill
University of North Carolina at Chapel Hill
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Confederate soldier Silent Sam, University of North Carolina at Chapel Hill by sculptor John Wilson.
University of North Carolina at Chapel Hill
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The Morehead Planetarium, designed by Eggers & Higgins, first opened in 1949.
16.
International Standard Book Number
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The International Standard Book Number is a unique numeric commercial book identifier. An ISBN is assigned to each variation of a book. For example, an e-book, a hardcover edition of the same book would each have a different ISBN. The ISBN is 13 digits long if assigned after 1 January 2007, 10 digits long if assigned before 2007. The method of assigning an ISBN varies from country to country, often depending on how large the publishing industry is within a country. The initial ISBN configuration of recognition was generated based upon the 9-digit Standard Book Numbering created in 1966. The 10-digit ISBN format was published in 1970 as international standard ISO 2108. The International Standard Serial Number, identifies periodical publications such as magazines; and the International Standard Music Number covers for musical scores. The ISBN configuration of recognition was generated in 1967 in the United Kingdom by Emery Koltay. The 10-digit ISBN format was published as international standard ISO 2108. The United Kingdom continued to use the 9-digit SBN code until 1974. The ISO on-line facility only refers back to 1978. An SBN may be converted by prefixing the digit "0". This can be converted to ISBN 0-340-01381-8; the digit does not need to be re-calculated. Since 1 ISBNs have contained 13 digits, a format, compatible with "Bookland" European Article Number EAN-13s.
International Standard Book Number
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A 13-digit ISBN, 978-3-16-148410-0, as represented by an EAN-13 bar code
17.
Standardization
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It can also facilitate commoditization of formerly custom processes. This view includes the case of "spontaneous standardization processes", to produce facto standards. The measures of the Indus civilisation also reached Persia and Central Asia, where they were further modified. Standardisation is also related to Processes. In view of large variations in units related to Civil, other Engineering streams, engineers united to overcome the situation and formed association. This association on gave birth to ISO in 1950. ISO stands for International Organisation for Standardisation. This voluntary organisation makes standards related to it. Certification as per ISO norms is popular all across world. Henry Maudslay developed the first industrially practical screw-cutting lathe in 1800. Before this, screw threads were usually made by filing. Nuts were rare; metal screws, when made at all, were usually for use in wood. Metal bolts passing to a metal fastening on the other side were usually fastened in non-threaded ways. This was a major advance in technology. Joseph Whitworth's thread measurements were adopted as the first national standard by companies around the country in 1841.
Standardization
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R. E. B. Crompton drew up the first international standards body, the International Electrotechnical Commission, in 1906.
Standardization
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Henry Maudslay 's famous early screw-cutting lathes of circa 1797 and 1800.
Standardization
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Memorial plaque of founding ISA in Prague.
18.
Measurement
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Measurement is the assignment of a number to a characteristic of an object or event, which can be compared with other objects or events. The scope and application of a measurement is dependent on the context and discipline. Measurement is a cornerstone of quantitative research in many disciplines. Historically, many measurement systems existed for the varied fields of human existence to facilitate comparisons in these fields. Often these were achieved by local agreements between trading partners or collaborators. Since the 18th century, developments progressed towards unifying, widely accepted standards that resulted in the modern International System of Units. This system reduces all physical measurements to a mathematical combination of seven base units. The science of measurement is pursued in the field of metrology. The measurement of a property may be categorized by the following criteria: uncertainty. They enable unambiguous comparisons between measurements. The type or level of measurement is a taxonomy for the methodological character of a comparison. For example, two states of a property may be compared by preference. The type is commonly not explicitly expressed, but implicit in the definition of a measurement procedure. The magnitude is the numerical value of the characterization, usually obtained with a suitably chosen measuring instrument. An uncertainty represents the systemic errors of the procedure; it indicates a level in the measurement.
Measurement
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A typical tape measure with both metric and US units and two US pennies for comparison
Measurement
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A baby bottle that measures in three measurement systems, Imperial (U.K.), U.S. customary, and metric.
Measurement
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Four measuring devices having metric calibrations