The Virginia Plan was a proposal by Virginia delegates for a bicameral legislative branch. The plan was drafted by James Madison while he waited for a quorum to assemble at the Constitutional Convention of 1787; the Virginia Plan was notable for its role in setting the overall agenda for debate in the convention and, in particular, for setting forth the idea of population-weighted representation in the proposed national legislature. It existed along side the New Jersey Plan for the structure of the United States government, formed in response to the Virginia Plan to protect small states' interests; the Constitutional Convention gathered in Philadelphia to revise the Articles of Confederation. The Virginia delegation took the initiative to frame the debate by drawing up and presenting a proposal, for which delegate James Madison is given chief credit. However, it was Edmund Randolph, the Virginia governor at the time, who put it before the convention on May 29, 1787, in the form of 15 resolutions.
The scope of the resolutions, going well beyond tinkering with the Articles of Confederation, succeeded in broadening the debate to encompass fundamental revisions to the structure and powers of the national government. The resolutions proposed, for example. One contentious issue facing the convention was the manner in which large and small states would be represented in the legislature: proportionate to population, with larger states having more votes than less-populous states, or by equal representation for each state, regardless of its size and population; the latter system more resembled that of the Articles of Confederation, under which each state was represented by one vote in a unicameral legislature. The Virginia Plan proposed a legislative branch consisting of two chambers, with the dual principles of rotation in office and recall applied to the lower house of the national legislature; each of the states would be represented in proportion to their "Quotas of contribution, or to the number of free inhabitants."
States with a large population, like Virginia, would thus have more representatives than smaller states. Large states supported this plan, smaller states opposed it, preferring an alternative put forward on June 15; the New Jersey Plan proposed a single-chamber legislature in which each state, regardless of size, would have one vote, as under the Articles of Confederation. In the end, the convention settled on the Connecticut Compromise, creating a House of Representatives apportioned by population and a Senate in which each state is represented. In addition to dealing with legislative representation, the Virginia Plan addressed other issues as well, with many provisions that did not make it into the Constitution that emerged, it called for a national government of three branches: legislative and judicial. Members of one of the two legislative chambers would be elected by the people; the executive would be chosen by the legislative branch. Terms of office were not specified, but the executive and members of the popularly elected legislative chamber could not be elected for an undetermined time afterward.
Additionally, the plan proposed that the legislative branch would have the power to negative state laws if they were deemed incompatible with the articles of union, or the states were deemed incompetent. The concept of checks and balances was embodied in a provision that legislative acts could be vetoed by a council composed of the executive and selected members of the judicial branch; the Virginia Plan and the debate surrounding it are prominently featured in the 1989 film A More Perfect Union, which depicts the events of the 1787 Constitutional Convention. Presented from the viewpoint and words of James Madison, the movie was filmed in Independence Hall
Federalist No. 51
Federalist No. 51, titled: "The Structure of the Government Must Furnish the Proper Checks and Balances Between the Different Departments", is an essay by James Madison, the fifty-first of The Federalist Papers. This document was published on February 8, 1788, under the pseudonym Publius, the name under which all The Federalist papers were published. Federalist No. 51 addresses means by which appropriate checks and balances can be created in government and advocates a separation of powers within the national government. This idea of checks and balances became a crucial document in the establishment of the modern U. S. system of checks and balances. One of its most important ideas, an explanation of check and balances, is the quoted phrase, "Ambition must be made to counteract ambition." In creating this system, Madison's idea was that the politicians and the individuals in public service in the U. S. would all have proclamations and ideas that that they were passionate about and that they wanted to work hard to enact.
The logical solution to ensure that laws and strong ideas were not enacted by a small group of partisan individuals was to use a federalist system where each level of government had different branches, each branch having the authority to impact legislation proposed by other branches. One of the main ways that Federalist Paper 51 was able to encourage checks and balances was by emphasizing the word liberty and by describing that liberty would directly result from the implementation of these governmental concepts. Furthermore, Madison emphasized that although the branches were meant to have checks and balances, the branches would only function to their fullest extent if they were independent of one another. By being independent of one another, the branches would be able to focus on their purpose and the system of checks and balances would only come into play if disagreements and issues arose within the three branches; the "if men were angels" quote was meant to imply that not everyone has communal interests in mind and that certain governmental officials are going to push legislation, in their own interests, rather than in the interests of their constituents.
Madison emphasized that a system of checks and balances would prevent this from happening and he uses the quote to show that checks and balances are necessary because men are not all angels. This ties back into the ideas of liberty and equal opportunity that Madison seems to be trying to emphasize through this Federalist paper. In addition, the original idea of checks and balances was a European idea that had roots in the enlightenment period. Political philosophers such as Locke and Rousseau had ideas. Further, the idea of a representative democracy as a method of establishing these checks and balances is something, a pivotal component to the federalist paper because it helps understand how the different branches of government will be put into place. We see this idea of checks in balances in other countries, prior to the establishment of this system in the United States; this suggests that the idea of political separation of powers and of checks and balances in government, implemented in the Unites States is a universal concept, concrete in political theory.
The inclusion of this theory in Federalist 51 is reiteration of a sentiment, present on an international scale. The Federalist Papers, as a foundation text of constitutional interpretation, are cited by American jurists and court systems in general. Of all The Federalist papers, No. 51 is the fourth most-cited document. The purpose of No. 51 is, according to Madison, to inform the reader of the safeguards created by the convention to maintain the separate branches of government and to protect the rights of the people and of the country. The biggest threats to the government of the United States would be the ability of one governing branch to obtain too much power over another, of factions to cause a tyranny of the majority. Madison's key point is that the members of each department should have as little dependence as possible on the members of the other departments, to stay independent, their own department must not encroach on the others. To secure these ends, Madison suggests that "the great security against a gradual concentration of the several powers in the same department" is to enable each department to fend off attempts to encroach upon the government of each other's departments.
Each branch should have as little influence as possible in the appointment of members of other branches, should retain financial independence from one another to prevent corruption. In a republican form of government, Madison asserts, the legislative branch is the strongest, therefore must be divided into different branches, be as little connected with each other as possible, render them by different modes of election, he deems the legislative branch to be the strongest since it is the true voice of the people. He balances; the government is guarded against usurpations because it is divided into distinct and separate departments. In 1787, power over people was divided both through federalism and through branches within the national government; because of the division of power, a "double security arises to the rights of the people. The governments will control each other, at the same time that each will be controlled by itself". Madison discusses at great length the
National Audio-Visual Conservation Center
The National Audiovisual Conservation Center known as the Packard Campus for Audio-Visual Conservation, is the Library of Congress's audiovisual archive located inside Mount Pony in Culpeper, Virginia. From 1969 to 1988, the campus was a high-security storage facility operated by the Federal Reserve Board. With the approval of the United States Congress in 1997, it was purchased by the David and Lucile Packard Foundation from the Federal Reserve Bank of Richmond via a $5.5 million grant, done on behalf of the Library of Congress. With a further $150 million from the Packard Humanities Institute and $82.1 million from Congress, the facility was transformed into the National Audio-Visual Conservation Center, which completed construction in mid-2007, after transfer of the bulk of archives, opened for scheduled tours and visitors in fall 2008. The campus offered, for the first time, a single site to store all 6.3 million pieces of the library's movie and sound collection. Technically, the Packard Campus is just the largest part of the whole National Audio-Visual Conservation Center, which consists of the Library of Congress's Motion Picture and Television Division and Recorded Sound Division reference centers on Capitol Hill, the Mary Pickford Theater, any other Library of Congress audio-visual storage facilities that remain outside the Packard Campus.
The PCAVC design, named Best of 2007 by Mid-Atlantic Construction Magazine, involved upgrading the existing bunker and creating an new, below-ground entry building that includes a large screening room, office space and research facilities. Designers BAR Architects, project-architect SmithGroup and landscape designers SWA Group, along with DPR Construction, Inc. collaborated in what is now the largest green-roofed commercial facility in the eastern United States, blending into the surrounding environment and ecosystem. With Cold War tensions came fear that in the event of a nuclear war, the economy of the United States would be destroyed. In response to this, the United States Federal Reserve constructed a bunker to house enough U. S. currency to replenish the cash supply east of the Mississippi River in the event of a catastrophic event. Dedicated on December 10, 1969, the 400-foot-long, 140,000-square-foot radiation-hardened facility was constructed of steel-reinforced concrete one foot thick.
Lead-lined shutters could be dropped to shield the windows of the semi-recessed facility, covered by 2 to 4 feet of dirt and surrounded by barbed-wire fences and a guard post. The seven computers at the facility, operated by the Federal Reserve Bank of Richmond, were the central node for all American electronic funds transfer activities. Between 1969 and 1988, the bunker stored several billion dollars worth of U. S. currency, including a large number of $2 bills shrink-wrapped and stacked on pallets 9 feet high. Following a nuclear attack, this money was to be used to replenish currency supplies east of the Mississippi River. Prior to July 1992, the bunker served as a continuity of government facility. With a peacetime staff of 100, the site was designed to support an emergency staff of 540 for 30 days, but only 200 beds were provided in the men's and women's dormitories. A pre-planned menu of freeze-dried foods for the first 30 days of occupation was stored on site. Other noteworthy features of the facility were a cold storage area for maintaining bodies unable to be promptly buried, an incinerator, indoor pistol range, a helicopter landing pad.
The facility housed the Culpeper Switch, the central switching station of the Federal Reserve's Fedwire electronic funds transfer system, which at the time connected only the Fed's member banks. The Culpeper Switch served as a data backup point for member banks east of the Mississippi River. In 1988, all money was removed from Mount Pony; the Culpeper Switch ceased operation in 1992, its functions having been decentralized to three smaller sites. In addition, its status as continuity of government site was removed; the facility was poorly maintained by a skeleton staff until 1997 when the bunker was offered for sale. With the approval of the United States Congress, it was purchased by the David and Lucile Packard Foundation from the Federal Reserve Bank of Richmond via a $5.5 million grant, done on behalf of the Library of Congress. With a further $150 million from the Packard Humanities Institute and $82.1 million from Congress, the facility was transformed into the National Audio-Visual Conservation Center, which opened in mid-2007.
The center offered, for the first time, a single site to store all 6.3 million pieces of the library's movie and sound collection. The Packard Campus was designed to be a green building, being situated underground and topped with sod roofs, it was designed to have minimal visual impact on the Virginia countryside by blending into the existing landscape. From the northwest, only a semi-circular terraced arcade appears in the hill to allow natural light into the administrative and work areas. Additionally, the site included the largest private sector re-forestation effort on the Eastern Seaboard, amassing over 9,000 tree saplings and nearly 200,000 other plantings; the underground vaults contain nearly 90 miles of shelving, not including 124 nitrate film vaults: the largest nitrate film storage complex in the Western hemisphere. The campus's data center is the first archive to preserve digital content at the petabyte level; the campus al
Independence Avenue (Washington, D.C.)
Independence Avenue is a major east-west street in the southwest and southeast quadrants of the city of Washington, D. C. in the United States, running just south of the United States Capitol. Named South B Street, Independence Avenue SW was constructed between 1791 and 1823. Independence Avenue SE was constructed in pieces as residential development occurred east of the United States Capitol and east of the Anacostia River. Independence Avenue SW received its current name after Congress renamed the street in legislation approved on April 13, 1934. Independence Avenue SW had its western terminus at 14th Street SW, but was extended west to Ohio Drive SW between 1941 and 1942; the government of the District of Columbia renamed the portion of the road in the southeast quadrant of the city in 1950. In the District of Columbia's Cartesian-coordinate-based street-naming system, Independence Avenue was known as South B Street; the street began construction sometime after 1791. By October 1803, it existed definitively between New Jersey Avenue and 1st Street East, in 1809 it was opened between New Jersey Avenue and Pennsylvania Avenue.
By 1816, the entire length of the avenue appears to have been opened. At the time, South B Street's western terminus was on the shore of the Potomac River, which at the time was located where 14th Street NW is now. After terrible flooding inundated much of downtown Washington, D. C. in 1881, Congress ordered the United States Army Corps of Engineers to dredge a deep channel in the Potomac to lessen the chance of flooding. Congress ordered that the dredged material be used to fill in what remained of the Tiber Creek estuary and build up much of the land near the White House and along Pennsylvania Avenue NW by nearly 6 feet to form a kind of levee; this "reclaimed land" — which today includes West Potomac Park, East Potomac Park, the Tidal Basin — was complete by 1890, designated Potomac Park by Congress in 1897. Congress first appropriated money for the beautification of the reclaimed land in 1902, which led to the planting of sod and trees, but South B Street was not extended through the newly reclaimed land.
In 1925, Congress authorized the construction of Arlington Memorial Bridge. The legislation specified that North B Street be treated as a major approach to Arlington Memorial Bridge; the National Capital Park and Planning Commission approved the significant widening of North B Street into a ceremonial avenue. On February 25, 1931, President Herbert Hoover signed legislation which renamed North B Street as Constitution Avenue. Planning for the creation of a similar ceremonial avenue to take the place of South B Street began in 1930; that year, the National Capital Park and Planning Commission advocated turning the roadway into a much-widened ceremonial avenue as a counterpart to North B Street. The NCPPC proposed extending South B Street west via a bridge over the Tidal Basin as a means of alleviating the traffic congestion that occurred after the closure of 13th Street NW south of Constitution Avenue; the following year, the NCPPC proposed widening South B Street to 60 feet between New Jersey Avenue SE and 12th Street SW.
Between 12th and 14th Streets SW, the street would be 80 feet wide, to accommodate the piers supporting the planned pedestrian skyways linking the United States Department of Agriculture headquarters building with the new United States Department of Agriculture South Building. All along the route, the north curb would remain in place, while the south curb moved to accommodate the new widths; the NCPPC had won the support of the Architect of the Capitol for the plan, which agreed in 1930 to move the new House office building to the south in order to accommodate the wider avenue. The renaming of North B Street and the actions of the NCPPC encouraged local citizens to seek to rename South B Street as well. In April 1932, the Federation of Citizens Associations of Washington, D. C. petitioned Congress to rename South B Street "Washington Avenue" between the Washington Monument grounds and Pennsylvania Avenue SE. The idea was conceived by the federation's past president, Fred A. Emery, who observed that no major thoroughfare in the city commemorated George Washington.
But no action was taken in the 72nd United States Congress. Instead, Senate Joint Resolution 258 was introduced Arthur Capper in the United States Senate to change the name to Independence Avenue; the Senate Committee on the District of Columbia favorably reported the bill on February 28, 1933. But Congress adjourned on March 3 without further action; the NCPPC had not given up on the idea, however. In November 1933, it approved changing the width of South B Street between 12th and 14th Streets SW to 80 feet, which helped cement in place its plan for a "future Independence Avenue". At its meeting on January 18, 1934, it re-emphasized its support for the street's renaming. Congress acted swiftly to rename the street. On February 2, 1934, Senator James J. Davis submitted S. 194 to accomplish this purpose. The full Senate passed the bill on February 6; the bill went to the United States House of Representatives, where the House Committee on the District of Columbia reported the bill favorably on March 10.
However, the bill was held up as the House debated the Reciprocal Tariff Act. Worried that the bill might stall, the Washington Board of Trade endorsed the legislation on March 30. On April 5, Representative Mary T. Norton, chair of the House District of Columbia Committee, broke the lo
Origins of the War of 1812
The War of 1812, a war between the United States, Great Britain, Britain's Indian allies, lasted from 1812 to 1815. The U. S. declared. There were several causes for the U. S. declaration of war: First, a series of trade restrictions introduced by Britain to impede American trade with France, a country with which Britain was at war. S. vessels into the Royal Navy. An implicit but powerful motivation for the Americans was the desire to uphold national honor in the face of what they considered to be British insults. American expansion into the Northwest was impeded by Indian raids; some historians maintain that an American goal in the war was annex some or all of Canada, a view that many Canadians still share, while others argue that inducing the fear of such a seizure had been a U. S. tactic designed to obtain a bargaining chip. Some members of the British Parliament at the time and dissident American politicians such as John Randolph of Roanoke claimed that land hunger rather than maritime disputes was the main motivation for the American declaration.
However, some historians, both Canadian and American, retain the view that desire to annex all or part of Canada was an American goal. Although the British made some concessions before the war on neutral trade, they insisted on the right to reclaim their deserting sailors; the British had the long-standing goal of creating a large "neutral" Indian state that would cover much of Ohio and Michigan. They made the demand as late as 1814 at the peace conference, but lost battles that would have validated their claims; the war was fought in four theatres: on the oceans, where the warships and privateers of both sides preyed on each other's merchant shipping. S., blockaded with increasing severity by the British, who mounted large-scale raids in the stages of the war. S. from Upper and Lower Canada. During the course of the war, both the Americans and British launched invasions of each other's territory, all of which were unsuccessful or gained only temporary success. At the end of the war, the British held parts of Maine and some outposts in the sparsely populated West while the Americans held Canadian territory near Detroit, but these occupied territories were restored at the end of the war.
In the United States, battles such as New Orleans and the earlier successful defence of Baltimore produced a sense of euphoria over a "second war of independence" against Britain. It ushered in an "Era of Good Feelings", in which the partisan animosity that had once verged on treason vanished. Canada emerged from the war with a heightened sense of national feeling and solidarity. Britain, which had regarded the war as a sideshow to the Napoleonic Wars raging in Europe, was less affected by the fighting; the British were engaged in a life-and-death war with Napoleon and could not allow the Americans to help the enemy, regardless of their lawful neutral rights to do so. As Horsman explains, "If possible, England wished to avoid war with America, but not to the extent of allowing her to hinder the British war effort against France. Moreover...a large section of influential British opinion, both in the government and in the country, thought that America presented a threat to British maritime supremacy."
The British had two goals: All parties were committed to the defeat of France, this required sailors, it required all-out commercial war against France. On the question of trade with America the British parties split; as Horsman argues, "Some restrictions on neutral commerce were essential for England in this period. That this restriction took such an extreme form after 1807 stemmed not only from the effort to defeat Napoleon, but from the undoubted jealousy of America's commercial prosperity that existed in England. America was unfortunate in that for most of the period from 1803 to 1812 political power in England was held by a group, pledged not only to the defeat of France, but to a rigid maintenance of Britain's commercial supremacy." That group was weakened by Whigs friendly to the U. S. in mid-1812 and the policies were reversed, but too late for the U. S. had declared war. By 1815 Britain was no longer controlled by politicians dedicated to commercial supremacy, so that cause had vanished.
The British were hindered by weak diplomats in Washington who misrepresented British policy and by communications that were so slow the Americans did not learn of the reversal of policy until they had declared war. When Americans proposed a truce based on British ending impressment, Britain refused, because it needed those sailors. Horsman explains, "Impressment, the main point of contention between England and America from 1803 to 1807, was made necessary because of England's great shortage of seam
United States Bill of Rights
The United States Bill of Rights comprises the first ten amendments to the United States Constitution. Proposed following the bitter 1787–88 debate over ratification of Constitution, written to address the objections raised by Anti-Federalists, the Bill of Rights amendments add to the Constitution specific guarantees of personal freedoms and rights, clear limitations on the government's power in judicial and other proceedings, explicit declarations that all powers not granted to the U. S. Congress by the Constitution are reserved for the people; the concepts codified in these amendments are built upon those found in earlier documents the Virginia Declaration of Rights, as well as the English Bill of Rights and the Magna Carta. Due to the efforts of Representative James Madison, who studied the deficiencies of the constitution pointed out by anti-federalists and crafted a series of corrective proposals, Congress approved twelve articles of amendment on September 25, 1789, submitted them to the states for ratification.
Contrary to Madison's proposal that the proposed amendments be incorporated into the main body of the Constitution, they were proposed as supplemental additions to it. Articles Three through Twelve were ratified as additions to the Constitution on December 15, 1791, became Amendments One through Ten of the Constitution. Article Two became part of the Constitution on May 1992, as the Twenty-seventh Amendment. Article One is still pending before the states. Although Madison's proposed amendments included a provision to extend the protection of some of the Bill of Rights to the states, the amendments that were submitted for ratification applied only to the federal government; the door for their application upon state governments was opened in the 1860s, following ratification of the Fourteenth Amendment. Since the early 20th century both federal and state courts have used the Fourteenth Amendment to apply portions of the Bill of Rights to state and local governments; the process is known as incorporation.
There are several original engrossed copies of the Bill of Rights still in existence. One of these is on permanent public display at the National Archives in Washington, D. C. Prior to the ratification and implementation of the United States Constitution, the thirteen sovereign states followed the Articles of Confederation, created by the Second Continental Congress and ratified in 1781. However, the national government that operated under the Articles of Confederation was too weak to adequately regulate the various conflicts that arose between the states; the Philadelphia Convention set out to correct weaknesses of the Articles, apparent before the American Revolutionary War had been concluded. The convention took place from May 14 to September 1787, in Philadelphia, Pennsylvania. Although the Convention was purportedly intended only to revise the Articles, the intention of many of its proponents, chief among them James Madison of Virginia and Alexander Hamilton of New York, was to create a new government rather than fix the existing one.
The convention convened in the Pennsylvania State House, George Washington of Virginia was unanimously elected as president of the convention. The 55 delegates who drafted the Constitution are among the men known as the Founding Fathers of the new nation. Thomas Jefferson, Minister to France during the convention, characterized the delegates as an assembly of "demi-gods." Rhode Island refused to send delegates to the convention. On September 12, George Mason of Virginia suggested the addition of a Bill of Rights to the Constitution modeled on previous state declarations, Elbridge Gerry of Massachusetts made it a formal motion. However, after only a brief discussion where Roger Sherman pointed out that State Bills of Rights were not repealed by the new Constitution, the motion was defeated by a unanimous vote of the state delegations. Madison an opponent of a Bill of Rights explained the vote by calling the state bills of rights "parchment barriers" that offered only an illusion of protection against tyranny.
Another delegate, James Wilson of Pennsylvania argued that the act of enumerating the rights of the people would have been dangerous, because it would imply that rights not explicitly mentioned did not exist. 84. Because Mason and Gerry had emerged as opponents of the proposed new Constitution, their motion—introduced five days before the end of the convention—may have been seen by other delegates as a delaying tactic; the quick rejection of this motion, however endangered the entire ratification process. Author David O. Stewart characterizes the omission of a Bill of Rights in the original Constitution as "a political blunder of the first magnitude" while historian Jack N. Rakove calls it "the one serious miscalculation the framers made as they looked ahead to the struggle over ratification". Thirty-nine delegates signed the finalized Constitution. Thirteen delegates left before it was completed, three who remained at the convention until the end refused to sign it: Mason and Edmund Randolph of Virginia.
Afterward, the Constitution was presented to the Articles of Confederation Congress with the request that it afterwards be submitted to a convention of delegates, chosen in each State by the people, for their assent and ratification. Following the Philadelphia Convention, some leading revolutionary figures such as Patrick Henry, Samuel Adams, Richard Henry Lee publicly opposed the new frame of government, a position known as "Anti-Federalism". Elbridge Gerry wrote the most popular Anti-Federalist tract, "Hon. Mr. Gerry's Objections"
Geographic coordinate system
A geographic coordinate system is a coordinate system that enables every location on Earth to be specified by a set of numbers, letters or symbols. The coordinates are chosen such that one of the numbers represents a vertical position and two or three of the numbers represent a horizontal position. A common choice of coordinates is latitude and elevation. To specify a location on a plane requires a map projection; the invention of a geographic coordinate system is credited to Eratosthenes of Cyrene, who composed his now-lost Geography at the Library of Alexandria in the 3rd century BC. A century Hipparchus of Nicaea improved on this system by determining latitude from stellar measurements rather than solar altitude and determining longitude by timings of lunar eclipses, rather than dead reckoning. In the 1st or 2nd century, Marinus of Tyre compiled an extensive gazetteer and mathematically-plotted world map using coordinates measured east from a prime meridian at the westernmost known land, designated the Fortunate Isles, off the coast of western Africa around the Canary or Cape Verde Islands, measured north or south of the island of Rhodes off Asia Minor.
Ptolemy credited him with the full adoption of longitude and latitude, rather than measuring latitude in terms of the length of the midsummer day. Ptolemy's 2nd-century Geography used the same prime meridian but measured latitude from the Equator instead. After their work was translated into Arabic in the 9th century, Al-Khwārizmī's Book of the Description of the Earth corrected Marinus' and Ptolemy's errors regarding the length of the Mediterranean Sea, causing medieval Arabic cartography to use a prime meridian around 10° east of Ptolemy's line. Mathematical cartography resumed in Europe following Maximus Planudes' recovery of Ptolemy's text a little before 1300. In 1884, the United States hosted the International Meridian Conference, attended by representatives from twenty-five nations. Twenty-two of them agreed to adopt the longitude of the Royal Observatory in Greenwich, England as the zero-reference line; the Dominican Republic voted against the motion, while Brazil abstained. France adopted Greenwich Mean Time in place of local determinations by the Paris Observatory in 1911.
In order to be unambiguous about the direction of "vertical" and the "horizontal" surface above which they are measuring, map-makers choose a reference ellipsoid with a given origin and orientation that best fits their need for the area they are mapping. They choose the most appropriate mapping of the spherical coordinate system onto that ellipsoid, called a terrestrial reference system or geodetic datum. Datums may be global, meaning that they represent the whole Earth, or they may be local, meaning that they represent an ellipsoid best-fit to only a portion of the Earth. Points on the Earth's surface move relative to each other due to continental plate motion and diurnal Earth tidal movement caused by the Moon and the Sun; this daily movement can be as much as a metre. Continental movement can be up to 10 m in a century. A weather system high-pressure area can cause a sinking of 5 mm. Scandinavia is rising by 1 cm a year as a result of the melting of the ice sheets of the last ice age, but neighbouring Scotland is rising by only 0.2 cm.
These changes are insignificant if a local datum is used, but are statistically significant if a global datum is used. Examples of global datums include World Geodetic System, the default datum used for the Global Positioning System, the International Terrestrial Reference Frame, used for estimating continental drift and crustal deformation; the distance to Earth's center can be used both for deep positions and for positions in space. Local datums chosen by a national cartographical organisation include the North American Datum, the European ED50, the British OSGB36. Given a location, the datum provides the latitude ϕ and longitude λ. In the United Kingdom there are three common latitude and height systems in use. WGS 84 differs at Greenwich from the one used on published maps OSGB36 by 112 m; the military system ED50, used by NATO, differs from about 120 m to 180 m. The latitude and longitude on a map made against a local datum may not be the same as one obtained from a GPS receiver. Coordinates from the mapping system can sometimes be changed into another datum using a simple translation.
For example, to convert from ETRF89 to the Irish Grid add 49 metres to the east, subtract 23.4 metres from the north. More one datum is changed into any other datum using a process called Helmert transformations; this involves converting the spherical coordinates into Cartesian coordinates and applying a seven parameter transformation, converting back. In popular GIS software, data projected in latitude/longitude is represented as a Geographic Coordinate System. For example, data in latitude/longitude if the datum is the North American Datum of 1983 is denoted by'GCS North American 1983'; the "latitude" of a point on Earth's surface is the angle between the equatorial plane and the straight line that passes through that point and through the center of the Earth. Lines joining points of the same latitude trace circles on the surface of Earth called parallels, as they are parallel to the Equator and to each other; the North Pole is 90° N. The 0° parallel of latitude is designated the Equator, the fun