Mammoth Lakes, California
Mammoth Lakes is a town in Mono County, the county's only incorporated community. It is located 9 miles northwest at an elevation of 7,880 feet; as of the 2010 United States Census, the population was 8,234, reflecting a 16% increase from the 2000 Census. The Mono people were the first settlers of the Mammoth Lakes area, thousands of years ago, they traveled by foot to other lands when trading with different tribes. The European history of Mammoth Lakes started in 1877, when four prospectors staked a claim on Mineral Hill, south of the current town, along Old Mammoth Road. In 1878, the Mammoth Mining Company was organized to mine Mineral Hill. By the end of 1878, 1500 people settled in the mining camp called Mammoth City. By 1880, the company had shut down, by 1888, the population declined to less than 10 people. By the early 1900s, the town of Mammoth was informally established near Mammoth Creek; the economics of the original town was based on logging and tourism. The first post office at Mammoth Lakes opened in 1923.
In 2004, the Mammoth Ski Museum opened in town. The museum featured many vintage artifacts and posters. A movie documenting the life of the founder of the ski resort and those of early famous skiers in the area is shown. In 2010, photographs taken by Dave McCoy were featured in an exhibit at the museum. In 2008, after a jury trial, the Mono County Superior Court entered a $43 million judgment against the Town of Mammoth Lakes for breach of a development agreement; the California Court of Appeal, Third District, affirmed the judgment in December 2010, the California Supreme Court declined to hear the appeal on March 23, 2011. On Monday July 2, 2012, Mammoth Lakes filed for bankruptcy in the face of the judgement; the same year, the bankruptcy was dismissed as a result of a settlement between the town and their largest creditor. According to the United States Census Bureau, the town has a total area of 25.3 square miles, of which 24.9 sq mi are land, 0.4 sq mi water. Mammoth Lakes lies on the edge of the Long Valley Caldera.
The area around the town is geologically active, with hot springs and rhyolite domes that are less than 1000 years old. Visitors can take State Route 203 from the town of Mammoth Lakes to the Mammoth Mountain Ski Area, over Minaret Summit down to Devils Postpile National Monument, with access to the Ansel Adams Wilderness; the area has natural hot springs. Other features include lakes, a soda springs, an obsidian dome. Mammoth Lakes is north of a scenic area with extensive hiking opportunities; the town is surrounded by mountains: on the west, Mammoth Mountain looms over the town, while to the south, the Sherwin Range dominates the view. This hilly terrain and the high altitude makes the area great for high-altitude athletic training, including among elite long-distance runners, who live and train in the thin air; the town is surrounded by acres of forest and is bordered by the Ansel Adams and John Muir Wilderness Areas. The eastern entrance of Yosemite National Park is located 32 miles north of town.
The town is situated in the mountainous part of Mono County, California. Mammoth Lakes has a warm summer mediterranean climate or a rare dry-summer continental climate for the 0 °C isoterm, with long snowy winters, warm, dry summers. Snowfall is heavy from December through March, averages 206 inches per season. On average, there are 21 days of 80 °F + highs, twenty-one days of highs under 32 °F and 4.6 nights of sub-0 °F lows annually. The 2010 United States Census reported that Mammoth Lakes had a population of 8,234; the population density was 325.4 people per square mile. The racial makeup of Mammoth Lakes was 6,643 White, 29 African American, 49 Native American, 128 Asian, 5 Pacific Islander, 1,151 from other races, 229 from two or more races. Hispanic or Latino of any race were 2,772 persons; the Census reported that 8,076 people lived in households, 158 lived in non-institutionalized group quarters, 0 were institutionalized. There were 3,229 households, out of which 942 had children under the age of 18 living in them, 1,401 were opposite-sex married couples living together, 177 had a female householder with no husband present, 144 had a male householder with no wife present.
There were 293 unmarried opposite-sex partnerships, 13 same-sex married couples or partnerships. 899 households were made up of individuals and 153 had someone living alone, 65 years of age or older. The average household size was 2.50. There were 1,722 families; the population was spread out with 1,719 people under the age of 18, 1,050 people aged 18 to 24, 2,833 people aged 25 to 44, 2,100 people aged 45 to 64, 532 people who were 65 years of age or older. The median age was 32.6 years. For every 100 females, there were 121.4 males. For every 100 females age 18 and over, there were 127.0 males. There were 9,626 housing units at an average density of 380.4 per square mile, of which 1,502 were owner-occupied, 1,727 were occupied by renters. The homeowner vacancy rate was 3.4%. 3,464 people lived in owner-occupied housing units and 4,612 people lived in rental housing units. As of the census of 2000, there were 7,093 people, 2,814 households, and
Embraer ERJ family
The Embraer ERJ family is a series of twin-engine regional jets produced by Embraer, a Brazilian aerospace company. Aircraft in the series include the ERJ135, ERJ140, ERJ145, as well as the Legacy business jet and the R-99 family of military aircraft; each jet in the series is powered by two turbofan engines. The family's primary competition comes from the Bombardier CRJ regional jets; the ERJ145 was designed for a perceived new market for regional jet aircraft, where the increased speed and passenger appeal would outweigh the inherent fuel economy of the turboprop aircraft which were in service and in development. The 45–48 seat EMB145 was launched at the Paris Airshow in 1989 as an 18 ft stretch of the EMB 120 Brasilia developed for $150M plus $50M for training and marketing, one third the cost of the cancelled Short Brothers FJX project, its $11M unit cost would have been $3M less than the Canadair CRJ. The 400 kn jet would be powered by GE/Garrett CFE738s, Lycoming ALF 502s or Rolls-Royce plc/Allison Engine AB580s turbofans, to be selected in the summer of 1989.
It was targeted for a late 1992 introduction with six produced ramping to 60 per year in 1995. It aimed for half of a market for 1000 with break-even. Keeping 75% of the Brasilia parts and systems, the EMB145 Amazon aimed for a 1991 first flight; the stretch resulted from two 11 ft plugs of the 7 ft 6 in diameter fuselage in the front and behind the redesigned 538 sq ft wing. Its supercritical airfoil with a 14% root thickness had its chord extended at the leading edge with a slight sweepback, increased aspect ratio and winglets; the overwing podded. Designed for 500–600 nmi stages, up to 1,400 nmi with a reduced payload, it had a 36,375 lb maximum takeoff weight and a 21,045 lb operating empty weight. In early 1990, no engine supplier willing to share the risk of the $250 million development was yet selected; the Allison GMA3007 was selected in March 1990, with a maximum 40 kN take-off thrust and growth capability to 45 kN, first flight was due in September 1991. Rolls could participate in the fan and LP turbine, its original responsibility on the RB.580 joint development.
By May it had 296 commitments from 19 operators, was seeking external finance. In June, maiden flight was expected by the end of 1990 before mid-1993 deliveries for $11.5 million each, cabin pressurisation was increased to 0.55 bar from the Brasilia 0.48 bar. Following the engine selection, design was revised: length decreased from 27.08 to 26.74 m, span increased from 22.37 to 22.49 m, aspect ratio to 9.3 from 9.2. MTOW rose from 16,500 to 18,500 kg, basic operating weight from 9,560 to 10,940 kg, maximum fuel from 3,900 to 4,210 kg and payload from 4,500 to 5,160 kg. wing loading increased from 330 to 370 kg/m2, time-to-climb to FL400 gained 5 min to 30 min and maximum cruise rose from 405 kn to 428 kn at FL360. First delivery in 1993 was slated to Comair, which ordered 60. In November 1990, a major reduction in Brazilian government spending, which held 61% of its voting share, resulted in Embraer sacking 32% of its 12,800 employees and suspending development of the EMB-145 for six months.
In March 1991, a revised configuration started wind tunnel testing: the quarter chord wing sweep increased to 22.3° with underslung engines for lower aerodynamic drag. This reduced the span by 2 to 20.5 m, reducing its aspect ratio from 9.3 to 8.4 and wing area from 50 to 47 m2. The semi-monocoque wing has two main and one auxiliary spar and holds 4,500 kg of fuel, it has double-slotted fowler flaps and spoilers. To accommodate the underwing engines, the landing gear is longer, allowing using jetways, the fuselage was lengthened from 25.8 to 26 m. In June 1991, the Brazilian Government loaned $600 million to Embraer and in July the programme was re-evaluated while tooling was 80% complete. By November 1991, Embraer, still looking for partners to share the risk of the $350 million project, hoping to obtain Government approval by the end of the year. Sold at $12 million with an all-digital cockpit and 31.8 kN engines, it had letters of intent for 337 units. First flight slipped to 1992 and certification for late 1993.
After re-evaluation late in 1991, the layout was revised again with two rear-fuselage-mounted engines and a Mach 0.8 cruise speed would be tested in the wind tunnel. Seat pitch is 79 cm. A further stretch to 50–55 passengers is limited by a 12° rotation angle. Embraer continued to look for partners to share the $350 million development as first flight was expected for late 1994. In December 1994, Embraer was privatised for 80% to Brazilian and US investors while 20% was kept by the Brazilian Government, it first flew on August 1995 with 18 firm orders, 16 options and 127 letters of intent. A 1,300h flight-test programme for the prototype and three pre-series aircraft was planned within 13 months for certification in the third quarter of 1996, before deliveries in the fourth quarter of 1996 to launch customer Flight West; the $14.5 million aircraft is developed with risk-sharing partners including Spain's Gamesa producing the wing. The standard maximum ramp weight is 19,300 and 20,300 kg for the exten
Piper PA-31 Navajo
The Piper PA-31 Navajo is a family of cabin-class, twin-engined aircraft designed and built by Piper Aircraft for the general aviation market, most using Lycoming engines. It was license-built in a number of Latin American countries. Targeted at small-scale cargo and feeder liner operations and the corporate market, the aircraft was a success, it continues to prove a popular choice, but due to decreased demand across the general aviation sector in the 1980s, production of the PA-31 ceased in 1984. At the request of company founder William T. Piper, Piper began development of a six- to eight-seat twin-engined corporate and commuter transport aircraft in 1962 under the project name Inca; the type, now designated the PA-31 and looking like a scaled-up Twin Comanche, was announced in late 1964 after its first flight on 30 September that year. It was a low-wing monoplane with a conventional tail, powered by two 310 hp Lycoming TIO-540-A turbocharged engines in so-called "tiger shark" cowlings, a feature shared with the Twin Comanche and the PA-23 Aztec.
As testing proceeded two cabin windows were added to each side of the fuselage and the engines moved further forward. The PA-31, now named "Navajo" after a Native American tribe, was not certified by the Federal Aviation Administration until 24 February 1966, deliveries did not begin until the following year, after the type was recertified in mid-1966 with an increase in maximum takeoff weight from 6,200 lb to 6,500 lb; the PA-31-300 was the next model, certified by the FAA in June 1967. This model was the only one of the PA-31 series not to have turbocharged engines. A pair of 300 hp Lycoming IO-540-M1A5 engines were fitted to the PA-31-300, driving two-bladed propellers. Following the introduction of the PA-31-300 the turbocharged model began to be known unofficially as the PA-31-310; the PA-31-300 was only produced in 1968 and 1969 and had the smallest production total for any PA-31 series model, with only 14 aircraft built. The next member of the family was Piper's first pressurized aircraft, the PA-31P Pressurized Navajo, certified in late 1969.
Development of the PA-31P had begun in January 1966, before the FAA had awarded the PA-31 a type certificate. The PA-31P was powered by 425 hp Lycoming TIGO-541-E engines and compared to earlier models had a longer nose and smaller windows, 25 US gal fuel tanks in the engine nacelles and a one-piece airstair cabin entry door instead of the split pair of doors on the unpressurized models. MTOW was increased at 7,800 lb. Known unofficially as the PA-31P-425, the PA-31P was produced from 1970 to 1977. In 1971 Piper introduced improvements to the PA-31 model; the Navajo B featured airconditioning, increased baggage space achieved by the addition of storage lockers in the rear part of extended nacelles, a third door next to the cabin entry doors to facilitate the loading of baggage, an optional separate door for the pilot to enter the cockpit. In September 1972, Piper unveiled the PA-31-350 Navajo Chieftain, a stretched version of the Navajo B with more powerful engines and counter-rotating propellers to prevent critical engine handling problems.
The fuselage was lengthened by 2 ft 0 in. Variants of the Lycoming TIO-540 developing 350 hp were fitted to the Chieftain, with an opposite-rotation LTIO-540 installed on the right-hand wing; the Chieftain's introduction was delayed by a flood at Piper's factory at Lock Haven, Pennsylvania caused by Hurricane Agnes, deliveries did not commence until 1973. In 1974, Piper used a Navajo B as the basis for developing a new model, the PA-31-325 Navajo C/R; the Navajo C/R had lower-power versions of the counter-rotating engines of the Chieftain, rated at 325 hp. After certification of the PA-31-325 in May 1974, production commenced in the 1975 model year; the Navajo B was superseded in the 1975 model year, by the Navajo C version of the PA-31 model. Piper established its T1000 Airliner Division in May 1981 at Florida factory. There were two aircraft in the T1000 series; the T1020, or more the PA-31-350T1020 was a PA-31-350 Chieftain optimized for and marketed for the commuter airline market. It featured reduced fuel capacity compared to the standard Chieftain, with the 40 US gal auxiliary fuel tanks in each wing of the Chieftain not fitted to the T1020.
It had reduced baggage capacity and up to eleven seats. The first T1020 was delivered in December 1981; the second aircraft in the T1000 stable was the T1040 – the PA-31T3 model. The T1040 was a hybrid, featuring the main fuselage of the PA-31-350T1020 with the nose and tail of the PA-31T1 Cheyenne I; the wings were similar to the Cheyenne I's, but with reduced fuel capacity and baggage lockers in the engine nacelles similar to those of the Chieftain. An optional underbelly cargo pod was available; the Pratt & Whitney Canada PT6A-11 turboprop engines were the same as those of the Cheyenne I. Deliveries of the T1040 began in July 1982. A T1050 variant with a fuselage stretch of 11 ft 6 in and seating capacity for 17 was proposed as a factory conversion of existing aircraft, but did not proceed; the last member of the PA-31 family to enter production was the PA-31P-350 Mojave. Like the T1040 the Mojave was a hybrid, but whereas the T1040 was a turboprop Chieftain the Mojave was more or less a piston-engined version of the Cheyenne.
The Mojave combined the fuselage of the Cheyenne I with the tail of the Chieftain. The wings were similar to the Chieftain's, but with greater structural strength, a 4 ft increase in wingspan a
An air taxi is a small commercial aircraft which makes short flights on demand. In 2001 air taxi operations were promoted in the United States by a NASA and aerospace industry study on the potential Small Aircraft Transportation System and the rise of light-jet aircraft manufacturing. In Canada, air taxi operations are regulated by Transport Canada under Canadian Aviation Regulation 703; the Canadian definition of air taxi includes all commercial single engined aircraft, multi-engined helicopters flown by day visual flight rules by one pilot and all multi-engined, non-turbo-jet aircraft, with a maximum take-off weight 8,618 kg or less and nine or fewer passenger seats, that are used to transport people or goods or for sightseeing. In the US, air taxi and air charter operations are governed by Part 135 of the Federal Aviation Regulations, unlike the larger scheduled air carriers which are governed by more stringent standards of FAR Part 121. Air Taxi Association Commercial aviation General aviation Very light jet NCFlyPorts Passenger drone Fractional Jets ImagineAir Propair Skymax Airstream Jets
Handley Page Jetstream
The Handley Page HP.137 Jetstream is a small twin-turboprop airliner, with a pressurised fuselage. The aircraft was designed to meet the requirements of the United States commuter and regional airline market; the design was improved and built by British Aerospace as the BAe Jetstream 31 and BAe Jetstream 32, featuring different turboprop engines. Handley Page was in an awkward position in the 1960s, wishing to remain independent of the "big two" British companies, but without the money needed to develop a large new airliner that would keep it in the market. After studying the problem it decided that its next product would be a competitive small airliner instead, filling a niche it identified for a 12–18 seat high-speed design. American salesman and modification engineer Jack Riley claimed to have written the design specifications; the design garnered intense interest in the US when it was first introduced, an order for 20 had been placed before the drawings were complete. Charles Joy was responsible for the design.
The original design dates from 1965 as a 12-seat aircraft. The aircraft was a high-tail monoplane of conventional layout. Considerable attention was paid to streamlining in order to improve performance, which led to one of the design's more distinctive features, a long nose profile; the fuselage had a circular cross-section to ease pressurisation, allowing much-higher-altitude flights and consequent higher speed and comfort than competing unpressurised designs. One drawback of the design was that fuselage was so small in cross-section that the cabin floor had to be "lowered" to allow stand-up passenger entry and egress through the rear door; this meant. Final assembly took place in a new factory at the Radlett aerodrome, but large portions of the structure were subcontracted, including complete wings being built by Scottish Aviation at Prestwick and the tail section by Northwest Industries of Edmonton, Canada; the original design used Turbomeca Astazou XIV engines of 840 hp, flew on 18 August 1967 as the Jetstream 1.
Throughout the test program the engines proved to be a weak point, being underpowered for the design, temperamental for what was a mature and used turboshaft design. Testing was moved to the Turboméca factory airfield in the south of France, both to allow faster turnaround with engine work, in order to improve the schedule by taking advantage of the better weather. In order to improve sales prospects in the US, the fifth prototype was fitted with the US-built Garrett TPE-331 in place of the French Astazou. Changing to the US-built engine was enough to allow the United States Air Force to consider it for cargo use, it placed an order for 11, fitted with a cargo door and accommodation for 12 passengers or six stretcher cases, to be known as the C-10A, or Jetstream 3M. The US Air Force cancelled its order in October 1969 citing late delivery; the first production model Jetstream 1 flew on 6 December 1968, over the next year 36 would be delivered. However, by this point Handley Page had given up on the original engine, the Jetstream 2 was launched with the larger 965 hp Astazou XVI, starting deliveries in late 1969.
The late delivery and engine problems had driven development costs to over £13 million, far more than the original £3 million projections. Only three Jetstream 2s would be completed before Handley Page went bankrupt, the production line was shut down in 1970. There was enough interest in the design that it was first picked up by a collaboration of investors and Scottish Aviation which formed a company called "Jetstream Aircraft" to produce the aircraft. A further ten Jetstream 1s were produced by this team. Scottish Aviation continued production of the Jetstream 2 as well, although referring to it as the Jetstream 200. In February 1972, 26 Jetstream 201s were ordered by the Royal Air Force, which used them as multi-engine trainers as the Jetstream T.1. Fourteen of these were modified as observer trainers for the Royal Navy, receiving the designation Jetstream T2. Jetstream Mk 1 Jetstream 200 Jetstream 3M Improved variant with TPE331 engines for the United States Air Force. C-10A United States Air Force military designation for the Jetstream 3M, production started but order cancelled and none delivered.
Riley Jetstream A few early Jetstream 1 aircraft were converted by Riley Aircraft of Carlsbad, California, to this version. The aircraft were fitted with two PT6A turboprop engines. Jetstream T1 United Kingdom military designation of Mk 1s for the Royal Air Force as multi-engine trainers. Jetstream T2 Conversion of T1s for the Royal Navy as rear-crew trainers. Century III Conversions with TPE331 engines; the aircraft was used by corporate operators and scheduled passenger commuter/regional airlines. ArgentinaAero VIP LibyaBuraq Air ColombiaADA SARPA Vertical de Aviación DenmarkNewair GermanyBavaria Fluggesellschaft United StatesAir Illinois Air US Apollo Airways Big Sky Airlines Dorado Wings Cal-State Air Lines JetAire Airlines Interstate Airlines Sierra Pacific Airlines South Central Air Transport Sun Airlines Texas Star Airways Western Air Stages Zia Airlines United KingdomRoyal Air Force retired 2003. Royal Navy retired 2011. UruguayUruguayan Navy former Royal Navy T2s. Retired 2010. 6 March 1970 D-INAH of Bavaria Fluggesellschaft crashed.
17 April 1981, Centur
The elevation of a geographic location is its height above or below a fixed reference point, most a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational surface. The term elevation is used when referring to points on the Earth's surface, while altitude or geopotential height is used for points above the surface, such as an aircraft in flight or a spacecraft in orbit, depth is used for points below the surface. Elevation is not to be confused with the distance from the center of the Earth. Due to the equatorial bulge, the summits of Mount Everest and Chimborazo have the largest elevation and the largest geocentric distance. GIS or geographic information system is a computer system that allows for visualizing, manipulating and storage of data with associated attributes. GIS offers better understanding of relationships of the landscape at different scales. Tools inside the GIS allow for manipulation of data for spatial cartography. A topographical map is the main type of map used to depict elevation through use of contour lines.
In a Geographic Information System, digital elevation models are used to represent the surface of a place, through a raster dataset of elevations. Digital terrain models are another way to represent terrain in GIS. USGS is developing a 3D Elevation Program to keep up with growing needs for high quality topographic data. 3DEP is a collection of enhanced elevation data in the form of high quality LiDAR data over the conterminous United States and the U. S. territories. There are three bare earth DEM layers in 3DEP which are nationally seamless at the resolution of 1/3, 1, 2 arcseconds; this map is derived from GTOPO30 data that describes the elevation of Earth's terrain at intervals of 30 arcseconds. It uses shading instead of contour lines to indicate elevation. Height Orthometric height Hypsography Geodesy Geodesy of North America Sea Level Datum of 1929 National Geodetic Vertical Datum of 1929 North American Vertical Datum of 1988 List of European cities by elevation List of highest mountains List of highest towns by country Normaal Amsterdams Peil Normalhöhennull Physical geography Table of the highest major summits of North America Temperature lapse rate Topographic isolation Topographic prominence Topography Vertical pressure variation U.
S. National Geodetic Survey website Geodetic Glossary @ NGS NGVD 29 to NAVD 88 online elevation converter @ NGS United States Geological Survey website Geographical Survey Institute Downloadable ETOPO2 Raw Data Database Downloadable ETOPO5 Raw Data Database Find the elevation of any place
The hectare is an SI accepted metric system unit of area equal to a square with 100-metre sides, or 10,000 m2, is used in the measurement of land. There are 100 hectares in one square kilometre. 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 hectare, remains as a non-SI unit accepted for use with the SI units, mentioned in Section 4.1 of the SI Brochure as a unit whose use is "expected to continue indefinitely". The name was coined from the Latin ārea; the metric system of measurement was first given a legal basis in 1795 by the French Revolutionary government. The law of 18 Germinal, Year III defined five units of measure: The metre for length The are for area The stère for volume of stacked firewood The litre for volumes of liquid The gram for massIn 1960, when the metric system was updated as the International System of Units, the are did not receive international recognition.
The International Committee for Weights and Measures makes no mention of the are in the current definition of the SI, but classifies the hectare as a "Non-SI unit accepted for use with the International System of Units". In 1972, the European Economic Community passed directive 71/354/EEC, which catalogued the units of measure that might be used within the Community; the units that were catalogued replicated the recommendations of the CGPM, supplemented by a few other units including the are whose use was limited to the measurement of land. The names centiare, deciare and hectare are derived by adding the standard metric prefixes to the original base unit of area, the are; the centiare is one square metre. The deciare is ten square metres; the are is a unit of area, used for measuring land area. It was defined by older forms of the metric system, but is now outside the modern International System of Units, it is still used in colloquial speech to measure real estate, in particular in Indonesia, in various European countries.
In Russian and other languages of the former Soviet Union, the are is called sotka. 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 deca and are, is equal to 10 ares or 1000 square metres. It is used in Norway and in the former Ottoman areas of the Middle East and the Balkans as a measure of land area. Instead of the name "decare", the names of traditional land measures are used, redefined as one decare: Stremma in Greece Dunam, donum, or dönüm in Israel, Jordan, Lebanon and Turkey Mål is sometimes used for decare in Norway, from the old measure of about the same area; the hectare, although not a unit of SI, is the only named unit of area, accepted for use within the SI. In practice the hectare is derived from the SI, being equivalent to a square hectometre, it is used throughout the world for the measurement of large areas of land, it is the legal unit of measure in domains concerned with land ownership and management, including law, agriculture and town planning throughout the European Union.
The United Kingdom, United States, to some extent Canada use the acre instead. Some countries that underwent a general conversion from traditional measurements to metric measurements required a resurvey when units of measure in legal descriptions relating to land were converted to metric units. Others, such as South Africa, published conversion factors which were to be used "when preparing consolidation diagrams by compilation". In many countries, metrication clarified existing measures in terms of metric units; the following legacy units of area have been redefined as being equal to one hectare: Jerib in Iran Djerib in Turkey Gong Qing in Hong Kong / mainland China Manzana in Argentina Bunder in The Netherlands The most used units are in bold. One hectare is equivalent to: 1 square hectometre 15 mǔ or 0.15 qǐng 10 dunam or dönüm 10 stremmata 6.25 rai ≈ 1.008 chō ≈ 2.381 feddan Conversion of units Hecto- Hectometre Order of magnitude Official SI website: Table 6. Non-SI units accepted for use with the International System of Units