Population density is a measurement of population per unit area or unit volume. It is applied to living organisms, most of the time to humans, it is a key geographical term. In simple terms population density refers to the number of people living in an area per kilometer square. Population density is population divided by total land water volume, as appropriate. Low densities may lead to further reduced fertility; this is called the Allee effect after the scientist. Examples of the causes in low population densities include: Increased problems with locating sexual mates Increased inbreeding For humans, population density is the number of people per unit of area quoted per square kilometer or square mile; this may be calculated for a county, country, another territory or the entire world. The world's population is around 7,500,000,000 and Earth's total area is 510,000,000 square kilometers. Therefore, the worldwide human population density is around 7,500,000,000 ÷ 510,000,000 = 14.7 per km2. If only the Earth's land area of 150,000,000 km2 is taken into account human population density is 50 per km2.
This includes all continental and island land area, including Antarctica. If Antarctica is excluded population density rises to over 55 people per km2. However, over half of the Earth's land mass consists of areas inhospitable to human habitation, such as deserts and high mountains, population tends to cluster around seaports and fresh-water sources. Thus, this number by itself does not give any helpful measurement of human population density. Several of the most densely populated territories in the world are city-states and dependencies; these territories have a small area and a high urbanization level, with an economically specialized city population drawing on rural resources outside the area, illustrating the difference between high population density and overpopulation The potential to maintain the agricultural aspects of deserts is limited as there is not enough precipitation to support a sustainable land. The population in these areas are low. Therefore, cities in the Middle East, such as Dubai, have been increasing in population and infrastructure growth at a fast pace.
Cities with high population densities are, by some, considered to be overpopulated, though this will depend on factors like quality of housing and infrastructure and access to resources. Most of the most densely populated cities are in Southeast Asia, though Cairo and Lagos in Africa fall into this category. City population and area are, however dependent on the definition of "urban area" used: densities are invariably higher for the central city area than when suburban settlements and the intervening rural areas are included, as in the areas of agglomeration or metropolitan area, the latter sometimes including neighboring cities. For instance, Milwaukee has a greater population density when just the inner city is measured, the surrounding suburbs excluded. In comparison, based on a world population of seven billion, the world's inhabitants, as a loose crowd taking up ten square feet per person, would occupy a space a little larger than Delaware's land area; the Gaza Strip has a population density of 5,046 pop/km.
Although arithmetic density is the most common way of measuring population density, several other methods have been developed to provide a more accurate measure of population density over a specific area. Arithmetic density: The total number of people / area of land Physiological density: The total population / area of arable land Agricultural density: The total rural population / area of arable land Residential density: The number of people living in an urban area / area of residential land Urban density: The number of people inhabiting an urban area / total area of urban land Ecological optimum: The density of population that can be supported by the natural resources Demography Human geography Idealized population Optimum population Population genetics Population health Population momentum Population pyramid Rural transport problem Small population size Distance sampling List of population concern organizations List of countries by population density List of cities by population density List of city districts by population density List of English districts by population density List of European cities proper by population density List of United States cities by population density List of islands by population density List of U.
S. states by population density List of Australian suburbs by population density Selected Current and Historic City, Ward & Neighborhood Density Duncan Smith / UCL Centre for Advanced Spatial Analysis. "World Population Density". Exploratory map shows data from the Global Human Settlement Layer produced by the European Commission JRC and the CIESIN Columbia University
The Hiberno-Scottish mission was a series of missions and expeditions initiated by various Irish clerics and cleric-scholars who, for the most part, are not known to have acted in concert. There was no overall coordinated mission, but there were sporadic missions initiated by Gaelic monks from Ireland and the western coast of modern-day Scotland, which contributed to the spread of Christianity and established monasteries in Britain and continental Europe during the Middle Ages; the earliest recorded Irish mission can be dated to 563 with the foundation of Iona by the Irish monk Saint Columba. Columba is said by Bede and Adamnán to have ministered to the Gaels of Dál Riada and converted the northern Pictish kingdoms. Over the next centuries more missions followed and spread through Anglo-Saxon England and the Frankish Empire; these early missions were, from the 18th and 19th centuries, so-called'Celtic Christianity', though aside from some idiosyncratic cultural features, it was orthodox and maintained relationships with the Holy See.
The Latin term Scotti refers to the Gaelic-speaking people of Ireland and the Irish who settled in western Scotland. In early medieval times Ireland was known as "Éire", "Hibernia" and "Scotia". By the end of the 11th century it referred to Gaelic Scotland, which had become Gaelicised by settlers from Ireland, from where the name Scotland derives. Thus, the "Scots" missionaries who so influential in the early Church history of Germany included men from both modern countries, though from Ireland. Schottenklöster is the name applied to the monastic foundations of Gaelic missionaries in Continental Europe to the Scottish Benedictine monasteries in Germany, which in the beginning of the 13th century were combined into one congregation whose abbot-general was the Abbot of the Scots monastery at Regensburg. Ireland's sobriquet "Island of Saints and Scholars" derives from this period, when scholars and missionaries from Ireland exerted great influence on Continental Europe. Irish abbot and missionary Columba founded the abbey of Iona off the western coast of modern-day Scotland in 563.
Following, the foundation of Lindisfarne in 635 by the Irish monk Saint Aidan. The missions continued throughout most Anglo-Saxon kingdoms during the following decades. Columbanus was active in the Frankish Empire from 590, establishing monasteries until his death at Bobbio in 615, he arrived on the continent with twelve companions and founded Annegray and Fontaines in France and Bobbio in Italy. During the 7th century the disciples of Columbanus and other Gaeil missionaries founded several monasteries in what are now France, Germany and Switzerland; the best known are: St. Gall in Switzerland, Disibodenberg in the Rhine Palatinate, St. Paul's at Besançon, Lure and Cusance in the Diocese of Besançon, Bèze in the Diocese of Langres, Remiremont Abbey and Moyenmoutier Abbey in the Diocese of Toul, Fosses-la-Ville in the Diocese of Liège, Mont Saint-Quentin at Péronne, Ebersmunster in Lower Alsace, St. Martin's at Cologne, the Scots Monastery, Vienna, Erfurt and Würzburg. In Italy, Fiesole produced Saint Donatus of Andrew the Scot of Fiesole.
Another early Schottenkloster was Säckingen in Baden, founded by the Irish missionary Fridolin of Säckingen, said to have founded another at Konstanz. Other Hiberno-Scottish missionaries active at the time, predominantly in Swabia, were Wendelin of Trier, Arbogast, Trudpert, Saint Gall, Corbinian and Rupert of Salzburg. Hiberno-Scottish activity in Europe continued after the death of Columbanus. There were monastic foundations in Anglo-Saxon England, the first in about 630 at "Cnobheresburgh", an unknown place in East Anglia but Burgh Castle mentioned by Bede. Others such as Malmesbury Abbey Bosham, Glastonbury Abbey had strong Irish links; the profile of Iona declined, from 698 until the reign of Charlemagne in the 770s, the Hiberno-Scottish efforts in the Frankish Empire were continued by the Anglo-Saxon mission – see Germanic Christianity. Irish monks known as Papar are said to have been present in Iceland before its settlement from AD 874 onwards by the Norse; the oldest source mentioning the Papar is the Íslendingabók, between 1122 and 1133.
Such figures are mentioned in the Icelandic Landnámabók which states that the Norse found Irish priests, with bells and crosiers, at Iceland at the time of their arrival. Among the Irish monks who were active in Central Europe were two important theologians, Marianus Scotus and Johannes Scotus Eriugena. Legends surrounding Irish foundations are recorded in a Middle High German text known as Charlemagne and the Scottish Saints; the rule of St. Columbanus, followed in most of these monasteries, was soon superseded by that of St. Benedict. Gaelic missionaries founded Honau in Baden, Murbach in Upper Alsace, Altomünster in Upper Bavaria, while other Gaelic monks restored St. Michel in Thiérache, Walsort near Namur, and, at Cologne, the Monasteries of St. Clement, St. Martin, St. Symphorian, St. Pantaléon. Towards the end of the 11th and in the 12th century a number of Schottenklöster, intended for Irish monks sprang up in Germany. About 1072, three monks, Marianus and Candidus, took up their abode at the little Church of Weih-St-Peter at Regensburg.
The term stained glass can refer to coloured glass as a material or to works created from it. Throughout its thousand-year history, the term has been applied exclusively to the windows of churches and other significant religious buildings. Although traditionally made in flat panels and used as windows, the creations of modern stained glass artists include three-dimensional structures and sculpture. Modern vernacular usage has extended the term "stained glass" to include domestic lead light and objects d'art created from foil glasswork exemplified in the famous lamps of Louis Comfort Tiffany; as a material stained glass is glass, coloured by adding metallic salts during its manufacture. The coloured glass is crafted into stained glass windows in which small pieces of glass are arranged to form patterns or pictures, held together by strips of lead and supported by a rigid frame. Painted details and yellow stain are used to enhance the design; the term stained glass is applied to windows in which the colours have been painted onto the glass and fused to the glass in a kiln.
Stained glass, as an art and a craft, requires the artistic skill to conceive an appropriate and workable design, the engineering skills to assemble the piece. A window must fit snugly into the space for which it is made, must resist wind and rain, especially in the larger windows, must support its own weight. Many large windows have withstood the test of time and remained intact since the Late Middle Ages. In Western Europe they constitute the major form of pictorial art to have survived. In this context, the purpose of a stained glass window is not to allow those within a building to see the world outside or primarily to admit light but rather to control it. For this reason stained glass windows have been described as "illuminated wall decorations"; the design of a window may be figurative. Windows within a building may be thematic, for example: within a church – episodes from the life of Christ. Stained glass is still popular today, but referred to as art glass, it is prevalent in luxury homes, commercial buildings, places of worship.
Artists and companies are contracted to create beautiful art glass ranging from domes, backsplashes, etc. During the late medieval period, glass factories were set up where there was a ready supply of silica, the essential material for glass manufacture. Silica requires a high temperature to melt, something not all glass factories were able to achieve; such materials as potash and lead can be added to lower the melting temperature. Other substances, such as lime, are added to rebuild the weakened network and make the glass more stable. Glass is coloured by adding metallic oxide powders or finely divided metals while it is in a molten state. Copper oxides produce green or bluish green, cobalt makes deep blue, gold produces wine red and violet glass. Much modern red glass is produced using copper, less expensive than gold and gives a brighter, more vermilion shade of red. Glass coloured while in the clay pot in the furnace is known as pot metal glass, as opposed to flashed glass. Using a blow-pipe, a "gather" of molten glass is taken from the pot heating in the furnace.
The gather is formed to a bubble of air blown into it. Using metal tools, molds of wood that have been soaking in water, gravity, the gather is manipulated to form a long, cylindrical shape; as it cools, it is reheated. During the process, the bottom of the cylinder is removed. Once brought to the desired size it is left to cool. One side of the cylinder is opened, it is put into another oven to heat and flatten it, placed in an annealer to cool at a controlled rate, making the material more stable. "Hand-blown" cylinder and crown glass were the types used in ancient stained-glass windows. Stained glass windows were in churches and chapels as well as many more well respected buildings; this hand-blown glass is created by blowing a bubble of air into a gather of molten glass and spinning it, either by hand or on a table that revolves like a potter's wheel. The centrifugal force causes the molten bubble to flatten, it can be cut into small sheets. Glass formed this way can be either coloured and used for stained-glass windows, or uncoloured as seen in small paned windows in 16th- and 17th-century houses.
Concentric, curving waves are characteristic of the process. The center of each piece of glass, known as the "bull's-eye", is subject to less acceleration during spinning, so it remains thicker than the rest of the sheet, it has the distinctive lump of glass left by the "pontil" rod, which holds the glass as it is spun out. This lumpy, refractive quality means the bulls-eyes are less transparent, but they have still been used for windows, both domestic and ecclesiastical. Crown glass is still made today, but not on a large scale. Rolled glass is produced by pouring molten glass onto a metal or graphite table and rolling it into a sheet using a large metal cylinder, similar to rolling out a pie crust; the rolling can be done by machine. Glass can be "double rolled", which means it is passed through two cylinders at once to yield glass of a specified thickness (typically about 1/8" or
East Anglia is a geographical area in the East of England. The area included has varied but the defined NUTS 2 statistical unit comprises the counties of Norfolk and Cambridgeshire, including the City of Peterborough unitary authority area; the name derives from the Anglo-Saxon kingdom of the East Angles, a tribe whose name originated in Anglia, northern Germany. Definitions of what constitutes; the Anglo-Saxon Kingdom of East Anglia, established in the 6th century consisted of the modern counties of Norfolk and Suffolk and expanded west into at least part of Cambridgeshire. The modern NUTS 2 statistical unit of East Anglia comprises Norfolk and Cambridgeshire; those three counties have formed the Roman Catholic Diocese of East Anglia since 1976, were the subject of a possible government devolution package in 2016. Essex has sometimes been included in definitions of East Anglia, including by the London Society of East Anglians. However, the Kingdom of Essex to the south, was a separate element of the Heptarchy of Anglo-Saxon England and did not identify as Angles but Saxons.
The county of Essex by itself forms a NUTS 2 statistical unit in the East of England region. Other definitions of the area have been proposed over the years. For example, the Redcliffe-Maud Report in 1969, which followed the Royal Commission on the Reform of Local Government, recommended the creation of eight provinces in England; the proposed East Anglia province would have included northern Essex, southern Lincolnshire and a small part of Northamptonshire as well as Cambridgeshire and Suffolk. The kingdom of East Anglia consisted of Norfolk and Suffolk, but upon the marriage of the East Anglian princess Etheldreda, the Isle of Ely became part of the kingdom; the kingdom was formed about the year 520 by the merging of the North and the South Folk and was one of the seven Anglo-Saxon heptarchy kingdoms. For a brief period following a victory over the rival kingdom of Northumbria around the year 616, East Anglia was the most powerful of the Anglo-Saxon kingdoms of England, its King Raedwald was Bretwalda.
However, this did not last and over the next forty years East Anglia was defeated by the Mercians twice and continued to weaken in relation to the other kingdoms. In 794, Offa of Mercia had king Æthelberht killed and took control of the kingdom himself. Although independence was temporarily restored by rebellion in 825, on 20 November 869 the Danes killed King Edmund and captured the kingdom. By 917, after a succession of Danish defeats, East Anglia was incorporated into the Kingdom of England by Edward the Elder, afterwards becoming an earldom. Despite some engineering work in the form of sea barriers constructed by the Roman Empire, much of East Anglia remained marshland and bogs until the 17th century. From this point onward a series of systematic drainage projects using drains and river diversions along the lines of Dutch practice, converted the alluvial land into wide swathes of productive arable land. In the 1630s thousands of Puritan families from East Anglia settled in the American region of New England, taking much East Anglian culture with them that can still be traced today.
East Anglia, which based much of its earnings on wool and arable farming, was a rich area of England until the effects of the Industrial Revolution saw manufacturing and development shift to the Midlands and the North. During the Second World War, the Royal Air Force and the United States Army Air Forces constructed many airbases in East Anglia for the heavy bomber fleets of the Combined Bomber Offensive against Nazi-occupied Europe. East Anglia was ideally suited to airfield construction as it comprises large areas of open, level terrain and is close to mainland Europe; the reduced flight time to mainland Europe therefore reduced the fuel load required and enabled a larger bomb load to be carried. Building the airfields was a massive civil engineering project and by the end of the war there was one every 8 miles. Many of these airfields can still be seen today from aerial photographs, a few remain in use today, the most prominent being Norwich International Airport. Pillboxes, which were erected in 1940 to help defend the nation against invasion, can be found throughout the area at strategic points.
East Anglia is bordered to the north and east by the North Sea, to the south by the estuary of the River Thames and shares an undefined land border to the west with the rest of England. Much of northern East Anglia is flat, low-lying and marshy, although the extensive drainage projects of the past centuries make this one of the driest areas in the UK. Inland much of the rest of Suffolk and Norfolk is undulating, with glacial moraine ridges providing some areas of steeper areas relief; the supposed flatness of the Norfolk landscape is noted in literature, such as Noël Coward's Private Lives – "Very flat, Norfolk". On the north-west corner East Anglia is bordered by a bay known as The Wash, where owing to deposits of sediment and land reclamation, the coastline has altered markedly within historical times. Conversely, over to the east on the coast exposed to the North Sea the coastline is subject to rapid erosion and has shifted inland since historic times. Major rivers include Suffolk's Stour, running through country beloved of the painter John Const
Round-tower churches are a type of church found in England in East Anglia. There is evidence of about 20 round-tower churches in Germany, of similar design and construction to those in East Anglia. Countries with at least one round-tower church include Andorra, the Czech Republic, France, Sweden, Norway and South Africa; the distinctive feature of these churches is their round towers. The reason for their construction – by the Anglo-Saxons – is a matter of dispute. Suggested explanations include the following: Round-tower churches are found in areas lacking normal building stone, are therefore built of knapped flint. Corners are difficult to construct in flint, hence the round walls of the towers; the churches are found in areas subject to raids from, for example, the Vikings, were built as defensive structures, churches being added later. In fact, the towers are too short to have been of much use defensively, the towers were added to existing churches, having flat walls where they joined the main structure.
In 937 King Athelstan, the first King of all England, decrees that a bell tower be built on the land of every thane. Many other explanations are offered in communities containing the churches, including appeals to ancient stone circles and the remains of wells. Round-tower churches should not be confused with shaped structures such as the Irish round towers found in Ireland and Scotland, or with round churches, which have a circular plan and are found in Denmark or Sweden. Great Shefford, St Mary Welford, St Gregory Bartlow, St Mary Snailwell, St Peter Lewes, St Michael Piddinghoe, St John Southease, St Peter Round Tower Churches Society Focus on Round Tower – by John Worrall W. J. Goode, Round Tower Churches of South East England Lyn Stilgoe and Dorothy Shreeve, The Round Tower Churches of Norfolk, Canterbury Press, Norwich.
In the Roman Republic and the Roman Empire, the Latin word castrum was a building, or plot of land, used as a fortified military camp. Castrum was the term used for different sizes of camps including a large legionary fortress, smaller auxiliary forts, temporary encampments, "marching" forts; the diminutive form castellum was used for fortlets occupied by a detachment of a cohort or a century. In English, the terms Roman fortress, Roman fort, Roman camp are used for castrum. However, scholastic convention tends toward the use of the words camp, marching camp, fortress as a translation of castrum. For a list of known castra see List of castra. Castrum appears in Oscan and Umbrian, two other Italic languages, suggests an origin at least as old as Proto-Italic language. Julius Pokorny traces a probable derivation from * k̂es -, schneiden in * k̂es - tro-m; these Italic reflexes based on * kastrom include Umbrian castruo, kastruvuf. They have the same meaning, says Pokorny, as Latin fundus, an estate, or tract of land.
This is not any land, but is a prepared or cultivated tract, such as a farm enclosed by a fence or a wooden or stone wall of some kind. Cornelius Nepos uses Latin castrum in that sense: when Alcibiades deserts to the Persians, Pharnabazus gives him an estate worth 500 talents in tax revenues; this is a change of meaning from the reflexes in other languages, which still mean some sort of knife, axe, or spear. Pokorny explains it as ’Lager’ als ‘abgeschnittenes Stück Land’, “a lager, as a cut-off piece of land.” If this is the civilian interpretation, the military version must be “military reservation,” a piece of land cut off from the common land around it and modified for military use. All castra must be defended by works no more than a stockade, for which the soldiers carried stakes, a ditch; the castra could be prepared under attack behind a battle line. Considering that the earliest military shelters were tents made of hide or cloth, all but the most permanent bases housed the men in tents placed in quadrangles and separated by numbered streets, one castrum may well have acquired the connotation of tent.
The commonest Latin syntagmata for the term castra are: castra stativa Permanent camp/fortresses castra aestiva Summer camp/fortresses castra hiberna Winter camp/fortresses castra navalia or castra nautica Navy camp/fortressesIn Latin the term castrum is much more used as a proper name for geographical locations: e.g. Castrum Album, Castrum Inui, Castrum Novum, Castrum Truentinum, Castrum Vergium; the plural was used as a place name, as Castra Cornelia, from this come the Welsh place name prefix caer- and English suffixes -caster and -chester. Castrorum Filius, "son of the camps," was one of the names used by the emperor Caligula and also by other emperors. Castro derived from Castrum, is a common Spanish family name as well as toponym in Italy, the Balkans and Spain and other Hispanophone countries, either by itself or in various compounds such as the World Heritage Site of Gjirokastër; the terms stratopedon and phrourion were used by Greek language authors to translate castrum and castellum, respectively.
A castrum was designed to house and protect the soldiers, their equipment and supplies when they were not fighting or marching. This most detailed description that survives about Roman military camps is De Munitionibus Castrorum, a manuscript of 11 pages that dates most from the late 1st to early 2nd century AD. Regulations required a major unit in the field to retire to a properly constructed camp every day. "… as soon as they have marched into an enemy's land, they do not begin to fight until they have walled their camp about. To this end a marching column ported the equipment needed to build and stock the camp in a baggage train of wagons and on the backs of the soldiers. Camps were the responsibility of engineering units to which specialists of many types belonged, officered by architecti, "chief engineers", who requisitioned manual labor from the soldiers at large as required, they could throw up a camp under enemy attack in as little as a few hours. Judging from the names, they used a repertory of camp plans, selecting the one appropriate to the length of time a legion would spend in it: tertia castra, quarta castra, etc..
More permanent camps were castra stativa. The least permanent of these were castra aestiva or aestivalia, "summer camps", in which the soldiers were housed sub pellibus or sub tentoriis, "under tents". Summer was the campaign season. For the winter the soldiers retired to castra hiberna containing barracks and other buildings of more solid materials, with timber construction being replaced by stone; the camp supplied army in the field. Neither the Celtic nor Germanic armies had this capability: they found it necessary to disperse after only a few days; the largest castra were legionary fortresses built as bases for one or more whole legions. From the time of Augustus more permanent castra with wooden or stone buildings and walls were introduced as the distant and hard-won boundaries of the expanding empire required permanent garrisons to control local and external threats
Gariannonum, or Gariannum, was a Saxon Shore fort in Norfolk, England. The Notitia Dignitatum, a Roman Army “order of battle” from about AD 400, lists nine forts of the Saxon Shore in south and east England, among which one was called Gariannonor, it has been much discussed over the years in terms of spelling and location. Gariannonum has been identified with Burgh Castle. However, modern reassessment of the Roman settlement 9 kilometres away at Caister-on-Sea has shown that it too had a military function. In Roman times, both sites lay on opposite sides of a large estuary; the identification of Burgh Castle as Gariannonum is uncertain, the name could apply to Caister-on-Sea. The name Gariannonum has been thought to derive from a Celtic root meaning "babbling river," which may refer to the River Yare at Burgh Castle, although the derivation is uncertain; the military function of Caister-on-Sea is open to doubt. Both sites operated together and one, or even both, were known by the Romans as Gariannonum.
Burgh Castle, English Heritage Caister Roman Site, English Heritage