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76-621: The channel is of glacial origin and is the submerged valley of the historic Saint Lawrence River , running 1,400 kilometres (870 mi) from a sharp escarpment downstream from the confluence of the St. Lawrence with the Saguenay River , past Anticosti Island and through the Gulf of St. Lawrence to the edge of the continental shelf off the island of Newfoundland . Its depth ranges from 180–550 metres (590–1,800 ft) with sub-tidal shelves on each side of

152-481: A geographic coordinate system as defined in the specification of the ISO 19111 standard. Since there are many different reference ellipsoids , the precise latitude of a feature on the surface is not unique: this is stressed in the ISO standard which states that "without the full specification of the coordinate reference system, coordinates (that is latitude and longitude) are ambiguous at best and meaningless at worst". This

228-560: A 300-by-300-pixel sphere, so illustrations usually exaggerate the flattening. The graticule on the ellipsoid is constructed in exactly the same way as on the sphere. The normal at a point on the surface of an ellipsoid does not pass through the centre, except for points on the equator or at the poles, but the definition of latitude remains unchanged as the angle between the normal and the equatorial plane. The terminology for latitude must be made more precise by distinguishing: Geographic latitude must be used with care, as some authors use it as

304-491: A survey but, with the advent of GPS , it has become natural to use reference ellipsoids (such as WGS84 ) with centre at the centre of mass of the Earth and minor axis aligned to the rotation axis of the Earth. These geocentric ellipsoids are usually within 100 m (330 ft) of the geoid. Since latitude is defined with respect to an ellipsoid, the position of a given point is different on each ellipsoid: one cannot exactly specify

380-549: A synonym for geodetic latitude whilst others use it as an alternative to the astronomical latitude . "Latitude" (unqualified) should normally refer to the geodetic latitude. The importance of specifying the reference datum may be illustrated by a simple example. On the reference ellipsoid for WGS84, the centre of the Eiffel Tower has a geodetic latitude of 48° 51′ 29″ N, or 48.8583° N and longitude of 2° 17′ 40″ E or 2.2944°E. The same coordinates on

456-524: Is 1,344,200 square kilometres (518,998.5 sq mi), of which 839,200 km (324,016.9 sq mi) is in Canada and 505,000 km (194,981.6 sq mi) is in the United States. The basin covers parts of Ontario and Quebec in Canada, parts of Minnesota , Wisconsin , Illinois , Indiana , Ohio , Pennsylvania , New York , Vermont , and nearly the entirety of the state of Michigan in

532-626: Is a large international river in the middle latitudes of North America connecting the Great Lakes to the North Atlantic Ocean . Its waters flow in a northeasterly direction from Lake Ontario to the Gulf of St. Lawrence , traversing Ontario and Quebec in Canada and New York in the United States. A section of the river demarcates the Canada–U.S. border . As the primary drainage outflow of

608-411: Is also used in the current literature. The parametric latitude is related to the geodetic latitude by: The alternative name arises from the parameterization of the equation of the ellipse describing a meridian section. In terms of Cartesian coordinates p , the distance from the minor axis, and z , the distance above the equatorial plane, the equation of the ellipse is: The Cartesian coordinates of

684-484: Is determined by the shape of the ellipse which is rotated about its minor (shorter) axis. Two parameters are required. One is invariably the equatorial radius, which is the semi-major axis , a . The other parameter is usually (1) the polar radius or semi-minor axis , b ; or (2) the (first) flattening , f ; or (3) the eccentricity , e . These parameters are not independent: they are related by Many other parameters (see ellipse , ellipsoid ) appear in

760-453: Is determined with the meridian altitude method. More precise measurement of latitude requires an understanding of the gravitational field of the Earth, either to set up theodolites or to determine GPS satellite orbits. The study of the figure of the Earth together with its gravitational field is the science of geodesy . The graticule is formed by the lines of constant latitude and constant longitude, which are constructed with reference to

836-624: Is home to the Thousand Islands . Today, the St. Lawrence River begins at the outflow of Lake Ontario and flows adjacent to Gananoque , Brockville , Morristown , Ogdensburg , Massena , Cornwall , Montreal , Trois-Rivières , and Quebec City before draining into the Gulf of St. Lawrence , often given as the largest estuary in the world. The estuary begins at the eastern tip of Île d'Orléans , just downstream from Quebec City. The river becomes tidal around Quebec City. The St. Lawrence River runs 3,058 kilometres (1,900  mi ) from

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912-583: Is not officially protected, the Laurentian Channel MPA could encompass a possible spawning ground. Much is still to be discovered regarding the life cycle of Atlantic cod which makes it a difficult species to protect using smaller, specific MPAs ( SLOSS Debate ). Thus, due to the large, undivided size of the Laurentian Channel MPA, the chance of protecting the region where Atlantic cod spawn is significantly higher. Saint Lawrence River The St. Lawrence River ( French : Fleuve Saint-Laurent )

988-462: Is of great importance in accurate applications, such as a Global Positioning System (GPS), but in common usage, where high accuracy is not required, the reference ellipsoid is not usually stated. In English texts, the latitude angle, defined below, is usually denoted by the Greek lower-case letter phi ( ϕ or φ ). It is measured in degrees , minutes and seconds or decimal degrees , north or south of

1064-575: Is that country's sixth oldest surviving European place-name. The earliest regular Europeans in the area were the Basques , who came to the St Lawrence Gulf and River in pursuit of whales from the early 16th century. The Basque whalers and fishermen traded with indigenous Americans and set up settlements, leaving vestiges all over the coast of eastern Canada and deep into the St. Lawrence River. Basque commercial and fishing activity reached its peak before

1140-451: Is the angle between the equatorial plane and the normal to the surface at that point: the normal to the surface of the sphere is along the radial vector. The latitude, as defined in this way for the sphere, is often termed the spherical latitude, to avoid ambiguity with the geodetic latitude and the auxiliary latitudes defined in subsequent sections of this article. Besides the equator, four other parallels are of significance: The plane of

1216-421: Is the meridional radius of curvature . The quarter meridian distance from the equator to the pole is For WGS84 this distance is 10 001 .965 729  km . The evaluation of the meridian distance integral is central to many studies in geodesy and map projection. It can be evaluated by expanding the integral by the binomial series and integrating term by term: see Meridian arc for details. The length of

1292-513: Is the second longest river in Canada. Lake Champlain and the Ottawa , Richelieu , Saint-Maurice , Saint-François , Chaudière and Saguenay rivers drain into the St. Lawrence. The St. Lawrence River is in a seismically active zone where fault reactivation is believed to occur along late Proterozoic to early Paleozoic normal faults related to the opening of the Iapetus Ocean . The faults in

1368-667: The Armada Invencible ' s disaster (1588), when the Basque whaling fleet was confiscated by King Philip II of Spain . Initially, the whaling galleons from Labourd were not affected by the Spanish defeat. Until the early 17th century, the French used the name Rivière du Canada to designate the St. Lawrence upstream to Montreal and the Ottawa River after Montreal. The St. Lawrence River served as

1444-505: The Philosophiæ Naturalis Principia Mathematica , in which he proved that a rotating self-gravitating fluid body in equilibrium takes the form of an oblate ellipsoid. (This article uses the term ellipsoid in preference to the older term spheroid .) Newton's result was confirmed by geodetic measurements in the 18th century. (See Meridian arc .) An oblate ellipsoid is the three-dimensional surface generated by

1520-618: The Great Lakes Basin , the St. Lawrence has the second-highest discharge of any river in North America (after the Mississippi River ) and the 16th-highest in the world. The estuary of St. Lawrence is often cited by scientists as the largest in the world. Significant natural landmarks of the river and estuary include the 1,864 river islands of the Thousand Islands , the endangered whales of Saguenay–St. Lawrence Marine Park , and

1596-653: The Gulf of St. Lawrence : Flowing through and adjacent to numerous Indigenous homelands, the river was a primary thoroughfare for many peoples. Beginning in Dawnland at the Gulf of St. Lawrence, the river borders Mi'kma'ki in the South (what is today known as the Canadian Maritimes ), and Nitassinan in the North, the national territory of the Innu people . On the south shore beyond

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1672-501: The Hudson River . The Accommodation with ten passengers made her maiden voyage from Montreal to Quebec City in 66 hours, for 30 of which she was at anchor. She had a keel of 75 feet, and a length overall of 85 feet. The cost of a ticket was eight dollars upstream, and nine dollars down. She had berths that year for twenty passengers. Within a decade, daily service was available in the hotly-contested Montreal-Quebec route. Because of

1748-872: The Mi'kmaw district of Gespe'gewa'ki , the river passes Wolastokuk (the Maliseet homeland), Pαnawαhpskewahki (the Penobscot homeland), and Ndakinna (the Abenaki homeland). Continuing, the river passes through the former country of the St. Lawrence Iroquois and then three of the six homelands of the Haudenosaunee : the Mohawk or Kanienʼkehá꞉ka , the Oneida or Onyota'a:ka , and the Onondaga or Onöñda’gaga’ . In

1824-670: The Thousand Islands chain near Alexandria Bay, New York and Kingston, Ontario ; the Hochelaga Archipelago , including the Island of Montreal and Île Jésus ( Laval ); the Lake St. Pierre Archipelago (classified a biosphere world reserve by the UNESCO in 2000) and the smaller Mingan Archipelago . Other islands include Île d'Orléans near Quebec City and Anticosti Island north of the Gaspé . It

1900-433: The geoid , a surface which approximates the mean sea level over the oceans and its continuation under the land masses. The second step is to approximate the geoid by a mathematically simpler reference surface. The simplest choice for the reference surface is a sphere , but the geoid is more accurately modeled by an ellipsoid of revolution . The definitions of latitude and longitude on such reference surfaces are detailed in

1976-571: The zenith ). On map projections there is no universal rule as to how meridians and parallels should appear. The examples below show the named parallels (as red lines) on the commonly used Mercator projection and the Transverse Mercator projection . On the former the parallels are horizontal and the meridians are vertical, whereas on the latter there is no exact relationship of parallels and meridians with horizontal and vertical: both are complicated curves. \ In 1687 Isaac Newton published

2052-591: The 10th of August feast day for Saint Lawrence in 1535. Indigenous people use the following names: In winter, the St. Lawrence River begins producing ice in December, with the formation of ice cubes between Montreal and Quebec City . The prevailing winds and currents push this ice towards the estuary, and it reaches the east of Les Méchins at the end of December. Ice covers the entire Gulf of St. Lawrence in January and February. Ice helps navigation by preventing

2128-687: The Appalachian division at all. The source of the North River in the Mesabi Range in Minnesota (Seven Beaver Lake) is considered to be the source of the St. Lawrence River. Because it crosses so many lakes, the water system frequently changes its name. From source to mouth, the names are: The St. Lawrence River also passes through Lake Saint-Louis and Lake Saint-Pierre in Quebec. The St. Lawrence River and

2204-447: The Earth's orbit about the Sun is called the ecliptic , and the plane perpendicular to the rotation axis of the Earth is the equatorial plane. The angle between the ecliptic and the equatorial plane is called variously the axial tilt, the obliquity, or the inclination of the ecliptic, and it is conventionally denoted by i . The latitude of the tropical circles is equal to i and the latitude of

2280-706: The Laurentian Channel AOI as a Marine Protected Area (MPA) under the Oceans Act . In April 2019, Fisheries and Oceans Canada designated the Laurentian Channel Marine Protected Area (MPA). The main purpose of the Laurentian Channel Marine Protected Area is to protect the biodiversity of the region. This MPA explicitly protects porbeagle sharks, smooth sakes, basking sharks, black dogfishes, northern wolffish, and leatherback sea turtles, along with sea pens and other cold water coral. Atlantic cod

2356-406: The St. Lawrence River includes: Large marine mammals travel in all the seas of the earth, the research and observations of these giants concern fishermen and shipping industry , exercise a fascination and a keen interest for laymen and, subjects of endless studies for scientists from Quebec, Canada and around the world. Thirteen species of cetaceans frequent the waters of the estuary and

Laurentian Channel - Misplaced Pages Continue

2432-622: The St. Lawrence to attack the city from the west, which they successfully did at the Battle of the Plains of Abraham . The river was used again by the British to defeat the French siege of Quebec under the Chevalier de Lévis in 1760. In 1809, the first steamboat to ply its trade on the St. Lawrence was built and operated by John Molson and associates, a scant two years after Fulton's steam-powered navigation of

2508-664: The Sun is overhead at some point of the Tropic of Capricorn . The south polar latitudes below the Antarctic Circle are in daylight, whilst the north polar latitudes above the Arctic Circle are in night. The situation is reversed at the June solstice, when the Sun is overhead at the Tropic of Cancer. Only at latitudes in between the two tropics is it possible for the Sun to be directly overhead (at

2584-773: The United States). The Seaway (including the Welland Canal ) now permits ocean-going vessels to pass all the way to Lake Superior . During the Second World War , the Battle of the St. Lawrence involved submarine and anti-submarine actions throughout the lower St. Lawrence River and the entire Gulf of St. Lawrence , Strait of Belle Isle and Cabot Strait from May to October 1942, September 1943, and again in October and November 1944. During this time, German U-boats sank several merchant marine ships and three Canadian warships. In

2660-523: The United States. The average discharge below the Saguenay River is 16,800 cubic metres per second (590,000 cu ft/s). At Quebec City, it is 12,101 m /s (427,300 cu ft/s). The average discharge at the river's source, the outflow of Lake Ontario, is 7,410 m /s (262,000 cu ft/s). The St. Lawrence River includes Lake Saint Francis at Salaberry-de-Valleyfield , Lake Saint-Louis south of Montreal and Lake Saint Pierre east of Montreal. It encompasses four archipelagoes :

2736-567: The WGS84 spheroid is The variation of this distance with latitude (on WGS84 ) is shown in the table along with the length of a degree of longitude (east–west distance): A calculator for any latitude is provided by the U.S. Government's National Geospatial-Intelligence Agency (NGA). The following graph illustrates the variation of both a degree of latitude and a degree of longitude with latitude. There are six auxiliary latitudes that have applications to special problems in geodesy, geophysics and

2812-425: The angle subtended at the centre by the meridian arc from the equator to the point concerned. If the meridian distance is denoted by m ( ϕ ) then where R denotes the mean radius of the Earth. R is equal to 6,371 km or 3,959 miles. No higher accuracy is appropriate for R since higher-precision results necessitate an ellipsoid model. With this value for R the meridian length of 1 degree of latitude on

2888-593: The area are rift -related and comprise the Saint Lawrence rift system . According to the United States Geological Survey, the St. Lawrence Valley is a physiographic province of the larger Appalachian division, containing the Champlain section. However, in Canada, where most of the valley is, it is instead considered part of a distinct St. Lawrence Lowlands physiographic division, and not part of

2964-506: The area. The Laurentian Channel contains the highest concentration of black dogfish in Canadian waters and is the only place where pupping occurs. It is an important spawning, nursery, and feeding area for a variety of species including porbeagle shark and smooth skate . Porbeagle sharks and basking sharks move into the area in the spring and reside there throughout the summer. One of only two known porbeagle shark mating grounds occurs within

3040-621: The centre of the Earth and perpendicular to the rotation axis intersects the surface at a great circle called the Equator . Planes parallel to the equatorial plane intersect the surface in circles of constant latitude; these are the parallels. The Equator has a latitude of 0°, the North Pole has a latitude of 90° North (written 90° N or +90°), and the South Pole has a latitude of 90° South (written 90° S or −90°). The latitude of an arbitrary point

3116-464: The channel by estuariane circulation. Over the 20th century, the bottom waters of the end of the channel (i.e. in the Saint Lawrence estuary) have become hypoxic . The Laurentian Channel is an ecologically important area, providing critical habitat for a variety of marine species, some of which are fished commercially and others that are not. Non-commercial species are part of the marine ecosystem in

Laurentian Channel - Misplaced Pages Continue

3192-457: The channel ranging in depths of less than 100 metres (330 ft). The channel ranges from a minimum width of 10 kilometres (6.2 mi) to as much as 55 kilometres (34 mi) at the Laurentian fan which is located at the edge of the continental shelf. Deep waters with temperatures between 2 and 6.5 °C (36 and 44 °F) enter the Gulf at the continental slope and are slowly advected up

3268-463: The channel. Two species at risk, the northern wolffish and the leatherback sea turtle , have been found in the area. In addition, at least 20 species of whales and dolphins have been observed in the area, as it is a critical feeding area and migration route into and out of the Gulf of St. Lawrence. The Laurentian Channel contains significant coral and sea pen populations, representing sensitive benthic habitats. Coral and sea pens are important to

3344-408: The datum ED50 define a point on the ground which is 140 metres (460 feet) distant from the tower. A web search may produce several different values for the latitude of the tower; the reference ellipsoid is rarely specified. The length of a degree of latitude depends on the figure of the Earth assumed. On the sphere the normal passes through the centre and the latitude ( ϕ ) is therefore equal to

3420-529: The early 17th century, the Huron-Wendat Nation migrated from their original country of Huronia to what is now known as Nionwentsïo centred around Wendake . Nionwentsïo occupies both the north and south shores of the river, overlapping with Nitassinan and the more western Wabanaki or Dawnland countries. Adjacent on the north shore is the Atikamekw territorial homeland of Nitaskinan and, upstream,

3496-464: The ecosystem and depend on the integrity of the sands and muds in the area for their survival. Of the variety of coral species found in the area, sea pens have been recorded in the greatest numbers and diversity, with the Laurentian Channel being described as having the highest sea pen concentrations within the entire Newfoundland and Labrador Shelves Bioregion. A portion of the Laurentian Channel

3572-402: The ellipsoid to that point Q on the surrounding sphere (of radius a ) which is the projection parallel to the Earth's axis of a point P on the ellipsoid at latitude ϕ . It was introduced by Legendre and Bessel who solved problems for geodesics on the ellipsoid by transforming them to an equivalent problem for spherical geodesics by using this smaller latitude. Bessel's notation, u ( ϕ ) ,

3648-509: The equator. For navigational purposes positions are given in degrees and decimal minutes. For instance, The Needles lighthouse is at 50°39.734′ N 001°35.500′ W. This article relates to coordinate systems for the Earth: it may be adapted to cover the Moon, planets and other celestial objects ( planetographic latitude ). For a brief history, see History of latitude . In celestial navigation , latitude

3724-521: The farthest headwater to the mouth and 1,197 km (743.8 mi) from the outflow of Lake Ontario. These numbers include the estuary; without the estuary, the length from Lake Ontario is c. 500 km (c. 300 mi). The farthest headwater is the North River in the Mesabi Range at Hibbing , Minnesota. Its drainage area, which includes the Great Lakes, the world's largest system of freshwater lakes,

3800-438: The following sections. Lines of constant latitude and longitude together constitute a graticule on the reference surface. The latitude of a point on the actual surface is that of the corresponding point on the reference surface, the correspondence being along the normal to the reference surface, which passes through the point on the physical surface. Latitude and longitude together with some specification of height constitute

3876-600: The formation of waves, and therefore spray, and prevents the icing of ships. With the draining of the Champlain Sea , due to a rebounding continent from the Last Glacial Maximum , the St. Lawrence River was formed. The Champlain Sea lasted from about 13,000 years ago to about 10,000 years ago and was continuously shrinking during that time, a process that continues today. The head of the St. Lawrence River, near Lake Ontario,

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3952-466: The further reaches of Anishinaabewaki, specifically the homelands of the Algonquin and Mississauga Nations. The Norse explored the Gulf of St. Lawrence in the 11th century and were followed by fifteenth- and early sixteenth-century European mariners, such as John Cabot , and the brothers Gaspar and Miguel Corte-Real . The first European explorer known to have sailed up the St. Lawrence River itself

4028-399: The geocentric latitude ( θ ) and the geodetic latitude ( ϕ ) is: For points not on the surface of the ellipsoid, the relationship involves additionally the ellipsoidal height h : where N is the prime vertical radius of curvature. The geodetic and geocentric latitudes are equal at the equator and at the poles but at other latitudes they differ by a few minutes of arc. Taking the value of

4104-618: The inland ports of the Great Lakes Waterway . The river has been called a variety of names by local First Nations . Beginning in the 16th century, French explorers visited what is now Canada and gave the river names such as the Grand fleuve de Hochelaga and the Grande rivière du Canada , where fleuve and rivière are two French words ( fleuve being a river that flows into the sea). The river's present name has been used since 1604 when it

4180-489: The largest tributaries of the Great Lakes . The St. Lawrence River tributaries are listed upstream from the mouth. The major tributaries of the inter-lake sections are also shown, as well as the major rivers that flow into the Great Lakes. Great Lakes tributaries are listed in alphabetical order. The list includes all tributaries with a drainage area of at least 1,000 square kilometres and an average flow of more than 10 cubic metres per second. tributary The diversity of

4256-522: The late 1970s, the river was the subject of a successful ecological campaign (called "Save the River"), originally responding to planned development by the United States Army Corps of Engineers . The campaign was organized, among others, by Abbie Hoffman . [[Category:Rivers Latitude In geography , latitude is a coordinate that specifies the north – south position of a point on

4332-451: The latitude and longitude of a geographical feature without specifying the ellipsoid used. Many maps maintained by national agencies are based on older ellipsoids, so one must know how the latitude and longitude values are transformed from one ellipsoid to another. GPS handsets include software to carry out datum transformations which link WGS84 to the local reference ellipsoid with its associated grid. The shape of an ellipsoid of revolution

4408-470: The limestone monoliths of the Mingan Archipelago . Long a transportation route to Indigenous peoples , the St. Lawrence River has played a key role in the history of Canada and in the development of cities such as Montreal and Quebec City . The river remains an important shipping route as the backbone of the St. Lawrence Seaway , a lock and canal system that enables world marine traffic to access

4484-399: The main route for European exploration of the North American interior, first pioneered by French explorer Samuel de Champlain . Control of the river was crucial to British strategy to capture New France in the Seven Years' War . Having captured Louisbourg in 1758, the British sailed up to Quebec the following year thanks to charts drawn up by James Cook . British troops were ferried via

4560-538: The meridian arc between two given latitudes is given by replacing the limits of the integral by the latitudes concerned. The length of a small meridian arc is given by When the latitude difference is 1 degree, corresponding to ⁠ π / 180 ⁠ radians, the arc distance is about The distance in metres (correct to 0.01 metre) between latitudes ϕ {\displaystyle \phi }  − 0.5 degrees and ϕ {\displaystyle \phi }  + 0.5 degrees on

4636-407: The polar circles is its complement (90° - i ). The axis of rotation varies slowly over time and the values given here are those for the current epoch . The time variation is discussed more fully in the article on axial tilt . The figure shows the geometry of a cross-section of the plane perpendicular to the ecliptic and through the centres of the Earth and the Sun at the December solstice when

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4712-448: The reference ellipsoid to the plane or in calculations of geodesics on the ellipsoid. Their numerical values are not of interest. For example, no one would need to calculate the authalic latitude of the Eiffel Tower. The expressions below give the auxiliary latitudes in terms of the geodetic latitude, the semi-major axis, a , and the eccentricity, e . (For inverses see below .) The forms given are, apart from notational variants, those in

4788-410: The rotation axis of the Earth. The primary reference points are the poles where the axis of rotation of the Earth intersects the reference surface. Planes which contain the rotation axis intersect the surface at the meridians ; and the angle between any one meridian plane and that through Greenwich (the Prime Meridian ) defines the longitude: meridians are lines of constant longitude. The plane through

4864-417: The rotation of an ellipse about its shorter axis (minor axis). "Oblate ellipsoid of revolution" is abbreviated to 'ellipsoid' in the remainder of this article. (Ellipsoids which do not have an axis of symmetry are termed triaxial .) Many different reference ellipsoids have been used in the history of geodesy . In pre-satellite days they were devised to give a good fit to the geoid over the limited area of

4940-468: The semi-major axis and the inverse flattening, ⁠ 1 / f ⁠ . For example, the defining values for the WGS84 ellipsoid, used by all GPS devices, are from which are derived The difference between the semi-major and semi-minor axes is about 21 km (13 miles) and as fraction of the semi-major axis it equals the flattening; on a computer monitor the ellipsoid could be sized as 300 by 299 pixels. This would barely be distinguishable from

5016-420: The sphere is 111.2 km (69.1 statute miles) (60.0 nautical miles). The length of one minute of latitude is 1.853 km (1.151 statute miles) (1.00 nautical miles), while the length of 1 second of latitude is 30.8 m or 101 feet (see nautical mile ). In Meridian arc and standard texts it is shown that the distance along a meridian from latitude ϕ to the equator is given by ( ϕ in radians) where M ( ϕ )

5092-403: The squared eccentricity as 0.0067 (it depends on the choice of ellipsoid) the maximum difference of ϕ − θ {\displaystyle \phi {-}\theta } may be shown to be about 11.5 minutes of arc at a geodetic latitude of approximately 45° 6′. The parametric latitude or reduced latitude , β , is defined by the radius drawn from the centre of

5168-406: The standard reference for map projections, namely "Map projections: a working manual" by J. P. Snyder. Derivations of these expressions may be found in Adams and online publications by Osborne and Rapp. The geocentric latitude is the angle between the equatorial plane and the radius from the centre to a point of interest. When the point is on the surface of the ellipsoid, the relation between

5244-420: The study of geodesy, geophysics and map projections but they can all be expressed in terms of one or two members of the set a , b , f and e . Both f and e are small and often appear in series expansions in calculations; they are of the order ⁠ 1 / 298 ⁠ and 0.0818 respectively. Values for a number of ellipsoids are given in Figure of the Earth . Reference ellipsoids are usually defined by

5320-400: The surface of the Earth or another celestial body. Latitude is given as an angle that ranges from −90° at the south pole to 90° at the north pole, with 0° at the Equator . Lines of constant latitude , or parallels , run east–west as circles parallel to the equator. Latitude and longitude are used together as a coordinate pair to specify a location on the surface of the Earth. On its own,

5396-406: The term "latitude" normally refers to the geodetic latitude as defined below. Briefly, the geodetic latitude of a point is the angle formed between the vector perpendicular (or normal ) to the ellipsoidal surface from the point, and the plane of the equator . Two levels of abstraction are employed in the definitions of latitude and longitude. In the first step the physical surface is modeled by

5472-407: The theory of map projections: The definitions given in this section all relate to locations on the reference ellipsoid but the first two auxiliary latitudes, like the geodetic latitude, can be extended to define a three-dimensional geographic coordinate system as discussed below . The remaining latitudes are not used in this way; they are used only as intermediate constructs in map projections of

5548-462: The virtually impassable Lachine Rapids , the St. Lawrence was once continuously navigable only as far as Montreal. Opened in 1825, the Lachine Canal was the first to allow ships to pass the rapids. An extensive system of canals and locks, known as the St. Lawrence Seaway , was officially opened on 26 June 1959 by Elizabeth II (representing Canada) and President Dwight D. Eisenhower (representing

5624-415: Was Jacques Cartier . At that time, the land along the river described as "about two leagues, a mountain as tall as a heap of wheat" was inhabited by the St. Lawrence Iroquoians . During Cartier's second voyage in 1535, because Cartier arrived in the estuary on Saint Lawrence 's feast day 10 August, he named it the Gulf of Saint Lawrence . The St. Lawrence River is today partly within the U.S. and as such

5700-491: Was identified as an Ecologically and Biologically Significant Area (EBSA) in 2007. On June 8, 2010, the Minister of Fisheries and Oceans Canada announced the Laurentian Channel as an Area of Interest (AOI). The AOI encompasses a portion of Laurentian Channel located off the southwest coast of Newfoundland and Labrador, an area of 11,619 square kilometres (4,486 sq mi). In June 2017, Fisheries and Oceans Canada (DFO) proposed

5776-460: Was recorded on a map by Samuel de Champlain Champlain opted for the names Grande riviere de sainct Laurens and Fleuve sainct Laurens in his writings, supplanting the earlier names. In contemporary French, the name is rendered as the fleuve Saint-Laurent . The name Saint-Laurent (Saint Lawrence) was originally applied to the eponymous bay by Jacques Cartier upon his arrival into the region on

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