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
A census is the procedure of systematically acquiring and recording information about the members of a given population. The term is used in connection with national population and housing censuses; the United Nations defines the essential features of population and housing censuses as "individual enumeration, universality within a defined territory and defined periodicity", recommends that population censuses be taken at least every 10 years. United Nations recommendations cover census topics to be collected, official definitions and other useful information to co-ordinate international practice; the word is of Latin origin: during the Roman Republic, the census was a list that kept track of all adult males fit for military service. The modern census is essential to international comparisons of any kind of statistics, censuses collect data on many attributes of a population, not just how many people there are. Censuses began as the only method of collecting national demographic data, are now part of a larger system of different surveys.
Although population estimates remain an important function of a census, including the geographic distribution of the population, statistics can be produced about combinations of attributes e.g. education by age and sex in different regions. Current administrative data systems allow for other approaches to enumeration with the same level of detail but raise concerns about privacy and the possibility of biasing estimates. A census can be contrasted with sampling in which information is obtained only from a subset of a population. Modern census data are used for research, business marketing, planning, as a baseline for designing sample surveys by providing a sampling frame such as an address register. Census counts are necessary to adjust samples to be representative of a population by weighting them as is common in opinion polling. Stratification requires knowledge of the relative sizes of different population strata which can be derived from census enumerations. In some countries, the census provides the official counts used to apportion the number of elected representatives to regions.
In many cases, a chosen random sample can provide more accurate information than attempts to get a population census. A census is construed as the opposite of a sample as its intent is to count everyone in a population rather than a fraction. However, population censuses rely on a sampling frame to count the population; this is the only way to be sure that everyone has been included as otherwise those not responding would not be followed up on and individuals could be missed. The fundamental premise of a census is that the population is not known and a new estimate is to be made by the analysis of primary data; the use of a sampling frame is counterintuitive as it suggests that the population size is known. However, a census is used to collect attribute data on the individuals in the nation; this process of sampling marks the difference between historical census, a house to house process or the product of an imperial decree, the modern statistical project. The sampling frame used by census is always an address register.
Thus it is not known how many people there are in each household. Depending on the mode of enumeration, a form is sent to the householder, an enumerator calls, or administrative records for the dwelling are accessed; as a preliminary to the dispatch of forms, census workers will check any address problems on the ground. While it may seem straightforward to use the postal service file for this purpose, this can be out of date and some dwellings may contain a number of independent households. A particular problem is what are termed'communal establishments' which category includes student residences, religious orders, homes for the elderly, people in prisons etc; as these are not enumerated by a single householder, they are treated differently and visited by special teams of census workers to ensure they are classified appropriately. Individuals are counted within households and information is collected about the household structure and the housing. For this reason international documents refer to censuses of housing.
The census response is made by a household, indicating details of individuals resident there. An important aspect of census enumerations is determining which individuals can be counted from which cannot be counted. Broadly, three definitions can be used: de facto residence; this is important to consider individuals who have temporary addresses. Every person should be identified uniquely as resident in one place but where they happen to be on Census Day, their de facto residence, may not be the best place to count them. Where an individual uses services may be more useful and this is at their usual, or de jure, residence. An individual may be represented at a permanent address a family home for students or long term migrants, it is necessary to have a precise definition of residence to decide whether visitors to a country should be included in the population count. This is becoming more important as students travel abroad for education for a period of several years. Other groups causing problems of enumeration are new born babies, people away on holiday, people moving home around census day, people without a fixed address.
People having second homes because of working in another part of the country or retaining a holiday cottage are dif
Arizona is a state in the southwestern region of the United States. It is part of the Western and the Mountain states, it is the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona shares the Four Corners region with Utah and New Mexico. Arizona is the 48th state and last of the contiguous states to be admitted to the Union, achieving statehood on February 14, 1912, coinciding with Valentine's Day. Part of the territory of Alta California in New Spain, it became part of independent Mexico in 1821. After being defeated in the Mexican–American War, Mexico ceded much of this territory to the United States in 1848; the southernmost portion of the state was acquired in 1853 through the Gadsden Purchase. Southern Arizona is known for its desert climate, with hot summers and mild winters. Northern Arizona features forests of pine, Douglas fir, spruce trees. There are ski resorts in the areas of Flagstaff and Tucson. In addition to the Grand Canyon National Park, there are several national forests, national parks, national monuments.
About one-quarter of the state is made up of Indian reservations that serve as the home of 27 federally recognized Native American tribes, including the Navajo Nation, the largest in the state and the United States, with more than 300,000 citizens. Although federal law gave all Native Americans the right to vote in 1924, Arizona excluded those living on reservations in the state from voting until the state Supreme Court ruled in favor of Native American plaintiffs in Trujillo v. Garley; the state's name appears to originate from an earlier Spanish name, derived from the O'odham name alĭ ṣonak, meaning "small spring", which applied only to an area near the silver mining camp of Planchas de Plata, Sonora. To the European settlers, their pronunciation sounded like "Arissona"; the area is still known as alĭ ṣonak in the O'odham language. Another possible origin is the Basque phrase haritz ona, as there were numerous Basque sheepherders in the area. A native Mexican of Basque heritage established the ranchería of Arizona between 1734 and 1736 in the current Mexican state of Sonora, which became notable after a significant discovery of silver there, c.
1737. There is a misconception. For thousands of years before the modern era, Arizona was home to numerous Native American tribes. Hohokam and Ancestral Puebloan cultures were among the many that flourished throughout the state. Many of their pueblos, cliffside dwellings, rock paintings and other prehistoric treasures have survived, attracting thousands of tourists each year; the first European contact by native peoples was with Marcos de Niza, a Spanish Franciscan, in 1539. He explored parts of the present state and made contact with native inhabitants the Sobaipuri; the expedition of Spanish explorer Coronado entered the area in 1540–1542 during its search for Cíbola. Few Spanish settlers migrated to Arizona. One of the first settlers in Arizona was José Romo de Vivar. Father Kino was the next European in the region. A member of the Society of Jesus, he led the development of a chain of missions in the region, he converted many of the Indians to Christianity in the Pimería Alta in the 1690s and early 18th century.
Spain founded presidios at Tubac in 1752 and Tucson in 1775. When Mexico achieved its independence from the Kingdom of Spain and its Spanish Empire in 1821, what is now Arizona became part of its Territory of Nueva California known as Alta California. Descendants of ethnic Spanish and mestizo settlers from the colonial years still lived in the area at the time of the arrival of European-American migrants from the United States. During the Mexican–American War, the U. S. Army occupied the national capital of Mexico City and pursued its claim to much of northern Mexico, including what became Arizona Territory in 1863 and the State of Arizona in 1912; the Treaty of Guadalupe Hidalgo specified that, in addition to language and cultural rights of the existing inhabitants of former Mexican citizens being considered as inviolable, the sum of US$15 million dollars in compensation be paid to the Republic of Mexico. In 1853, the U. S. acquired the land south below the Gila River from Mexico in the Gadsden Purchase along the southern border area as encompassing the best future southern route for a transcontinental railway.
What is now known as the state of Arizona was administered by the United States government as part of the Territory of New Mexico until the southern part of that region seceded from the Union to form the Territory of Arizona. This newly established territory was formally organized by the Confederate States government on Saturday, January 18, 1862, when President Jefferson Davis approved and signed An Act to Organize the Territory of Arizona, marking the first official use of the name "Territory of Arizona"; the Southern territory supplied the Confederate government with men and equipment. Formed in 1862, Arizona scout companies served with the Confederate States Army duri
La Paz County, Arizona
La Paz County is a county in the western part of the U. S. state of Arizona. As of the 2010 census, its population was 20,489, making it the second-least populous county in Arizona; the county seat is Parker. The name of the county is the Spanish word for "the peace", is taken from the early settlement of La Paz along the Colorado River. La Paz County was established in 1983 after voters approved separating the northern portion of Yuma County, making it the only county to be established after Arizona became a state in 1912, the second youngest county in the United States; the county did not have a large enough tax base to begin supporting a separate county government and had to rely on state money at first. As a result, Arizona laws were changed to make splitting other existing counties much more difficult. Under the revised Arizona laws, a county shall not be formed or divided by county initiative unless each proposed county would have all of the following characteristics: at least three-fourths of one percent of the total state assessed valuation and at least the statewide per capita assessed valuation.
A county formation commission is required to be formed to evaluate the feasibility of the proposed county. A proposal to divide a county must be approved by a majority of the votes cast in each proposed new county; the Colorado River Indian Reservation is located in the western portion of the county. Part of the reservation extends westward into San Riverside counties in California. According to the U. S. Census Bureau, the county has a total area of 4,514 sq mi, of which 4500 sq mi is land and 14 sq mi is water; the area that now makes up La Paz County was part of Yuma County. La Paz County hosts a variety of fauna; the endangered California Fan Palm, Washingtonia filifera grows in a few spots in the county. Mohave County - north Yavapai County - northeast Maricopa County - east Yuma County - south Imperial County, California - southwest Riverside County, California - west San Bernardino County, California - northwest Bill Williams River National Wildlife Refuge Cibola National Wildlife Refuge Imperial National Wildlife Refuge Kofa National Wildlife Refuge As of the 2000 census, there were 19,715 people, 8,362 households, 5,619 families residing in the county.
The population density was 4.4 people per square mile. There were 15,133 housing units at an average density of 3.4/sq mi. The racial makeup of the county was 74.15% white, 0.79% black or African American, 12.53% Native American, 0.41% Asian, 0.10% Pacific Islander, 9.35% from other races, 2.68% from two or more races. 22.42% of the population were Hispanic or Latino of any race. 18.90% reported speaking Spanish at home. There were 8,362 households, with 21.20% having children under the age of 18, 54.20% were married couples living together, 8.20% had a female householder with no husband present, 32.80% were non-families. 26.60% of households were made up of individuals and 12.90% had someone living alone, 65 years of age or older. The average household size was 2.32 and the average family size was 2.79. The county population had 21.10% under the age of 18, 6.10% from 18 to 24, 20.40% from 25 to 44, 26.60% from 45 to 64, 25.80% who were 65 years of age or older. The median age was 47 years. For every 100 females there were 105.50 males.
For every 100 females age 18 and over, there were 105.10 males. The median income for a household in the county was $25,839, the median income for a family was $29,141. Males had a median income of $26,642 versus $20,965 for females; the per capita income for the county was $14,916. About 13.60% of families and 19.60% of the population were below the poverty line, including 28.50% of those under age 18 and 12.90% of those age 65 or over. As of the 2010 census, there were 20,489 people, 9,198 households, 5,584 families residing in the county; the population density was 4.5//sq mi. There were 16,049 housing units at an average density of 3.56/sq mi. The racial makeup of the county was 69.8% white, 12.8% American Indian, 0.6% black or African American, 0.5% Asian, 12.5% from other races, 3.7% from two or more races. Those of Hispanic or Latino origin made up 23.5% of the population. In terms of ancestry, 22.4% were German, 15.9% were Irish, 15.3% were English, 2.1% were American. Of the 9,198 households, 19.3% had children under the age of 18 living with them, 47.2% were married couples living together, 9.4% had a female householder with no husband present, 39.3% were non-families, 32.1% of all households were made up of individuals.
The average household size was 2.19 and the average family size was 2.72. The median age was 53.9 years. The median income for a household in the county was $32,147 and the median income for a family was $37,721. Males had a median income of $35,464 versus $27,484 for females; the per capita income for the county was $21,165. About 14.3% of families and 20.3% of the population were below the poverty line, including 36.4% of those under age 18 and 6.5% of those age 65 or over. La Paz County is within Arizona's 4th congressional district represented by Republican Paul Gosar. Interstate 10 U. S. Route 95 U. S. Route 60 State Route 72 State Route 95 Avi Suquil
In law, an unincorporated area is a region of land, not governed by a local municipal corporation. Municipalities dissolve or disincorporate, which may happen if they become fiscally insolvent, services become the responsibility of a higher administration. Widespread unincorporated communities and areas are a distinguishing feature of the United States and Canada. In most other countries of the world, there are either no unincorporated areas at all, or these are rare. Unlike many other countries, Australia has only one level of local government beneath state and territorial governments. A local government area contains several towns and entire cities. Thus, aside from sparsely populated areas and a few other special cases all of Australia is part of an LGA. Unincorporated areas are in remote locations, cover vast areas or have small populations. Postal addresses in unincorporated areas, as in other parts of Australia use the suburb or locality names gazetted by the relevant state or territorial government.
Thus, there is any ambiguity regarding addresses in unincorporated areas. The Australian Capital Territory is in some sense an unincorporated area; the territorial government is directly responsible for matters carried out by local government. The far west and north of New South Wales constitutes the Unincorporated Far West Region, sparsely populated and warrants an elected council. A civil servant in the state capital manages such matters; the second unincorporated area of this state is Lord Howe Island. In the Northern Territory, 1.45% of the total area and 4.0% of the population are in unincorporated areas, including Unincorporated Top End Region, areas covered by the Darwin Rates Act—Nhulunbuy, Alyangula on Groote Eylandt in the northern region, Yulara in the southern region. In South Australia, 60% of the area is unincorporated and communities located within can receive municipal services provided by a state agency, the Outback Communities Authority. Victoria has 10 small unincorporated areas, which are either small islands directly administered by the state or ski resorts administered by state-appointed management boards.
Western Australia is exceptional in two respects. Firstly, the only remote area, unincorporated is the Abrolhos Islands, uninhabited and controlled by the WA Department of Fisheries. Secondly, the other unincorporated areas are A-class reserves either in, or close to, the Perth metropolitan area, namely Rottnest Island and Kings Park. In Canada, depending on the province, an unincorporated settlement is one that does not have a municipal council that governs over the settlement, it is but not always, part of a larger municipal government. This can range from small hamlets to large urbanized areas that are similar in size to towns and cities. For example, the urban service areas of Fort McMurray and Sherwood Park, of the Regional Municipality of Wood Buffalo and Strathcona County would be the fifth and sixth largest cities in Alberta if they were incorporated. In British Columbia, unincorporated settlements lie outside municipal boundaries and are administered directly by regional/county-level governments similar to the American system.
Unincorporated settlements with a population of between 100 and 1,000 residents may have the status of designated place in Canadian census data. In some provinces, large tracts of undeveloped wilderness or rural country are unorganized areas that fall directly under the provincial jurisdiction; some unincorporated settlements in such unorganized areas may have some types of municipal services provided to them by a quasi-governmental agency such as a local services board in Ontario. In New Brunswick where a significant population live in a Local Service District and services may come directly from the province; the entire area of the Czech Republic is divided into municipalities, with the only exception being 4 military areas. These are parts of the regions and do not form self-governing municipalities, but are rather governed by military offices, which are subordinate to the Ministry of Defense. † Brdy Military Area was abandoned by the Army in 2015 and converted into Landscape park, with its area being incorporated either into existing municipalities or municipalities newly established from the existing settlements.
The other four Military Areas were reduced in size in 2015 too. The decisions on whether the settlements join existing municipalities or form new ones are decided in plebiscites. Since Germany has no administrative level comparable to the townships of other countries, the vast majority of the country, close to 99%, is organized in municipalities consisting of multiple settlements which are not considered to be unincorporated; because these settlements lack a council of their own, there is an Ortsvorsteher / Ortsvorsteherin appointed by the municipal council, except in the smallest villages. In 2000, the number of unincorporated areas in Germany, called gemeindefreie Gebiete or singular gemeindefreies Gebiet, was 295 with a total area of 4,890.33 km² and around 1.4% of its territory. However
Poston is a census-designated place in La Paz County, United States, in Parker Valley. The population was 389 at the 2000 census. During World War II, Poston was the site of the Poston War Relocation Center, one of the United States' largest Japanese-American internment camps, where over 17,000 Japanese-Americans were held over a three-year period; the camp sites are now home to a monument dedicated to those interned there. Poston is located at 33°59′25″N 114°24′4″W. According to the United States Census Bureau, the CDP has a total area of 1.4 square miles, all of it land. As of the census of 2000, there were 389 people, 101 households, 92 families residing in the CDP; the population density was 279.9 people per square mile. There were 110 housing units at an average density of 79.1/sq mi. The racial makeup of the CDP was 31.36% White, 0.51% Black or African American, 17.22% Native American, 48.33% from other races, 2.57% from two or more races. 77.12% of the population were Hispanic or Latino of any race.
There were 101 households out of which 66.3% had children under the age of 18 living with them, 66.3% were married couples living together, 15.8% had a female householder with no husband present, 8.9% were non-families. 6.9% of all households were made up of individuals and 2.0% had someone living alone, 65 years of age or older. The average household size was 3.85 and the average family size was 3.92. In the CDP, the population was spread out with 41.9% under the age of 18, 10.8% from 18 to 24, 30.1% from 25 to 44, 13.1% from 45 to 64, 4.1% who were 65 years of age or older. The median age was 23 years. For every 100 females, there were 110.3 males. For every 100 females age 18 and over, there were 107.3 males. The median income for a household in the CDP was $17,625, the median income for a family was $17,065. Males had a median income of $15,859 versus $13,125 for females; the per capita income for the CDP was $6,938. About 41.5% of families and 46.3% of the population were below the poverty line, including 54.5% of those under age 18 and 18.2% of those age 65 or over
Race and ethnicity in the United States Census
Race and ethnicity in the United States Census, defined by the federal Office of Management and Budget and the United States Census Bureau, are self-identification data items in which residents choose the race or races with which they most identify, indicate whether or not they are of Hispanic or Latino origin. The racial categories represent a social-political construct for the race or races that respondents consider themselves to be and, "generally reflect a social definition of race recognized in this country." OMB defines the concept of race as outlined for the US Census as not "scientific or anthropological" and takes into account "social and cultural characteristics as well as ancestry", using "appropriate scientific methodologies" that are not "primarily biological or genetic in reference." The race categories include both national-origin groups. Race and ethnicity are considered separate and distinct identities, with Hispanic or Latino origin asked as a separate question. Thus, in addition to their race or races, all respondents are categorized by membership in one of two ethnic categories, which are "Hispanic or Latino" and "Not Hispanic or Latino".
However, the practice of separating "race" and "ethnicity" as different categories has been criticized both by the American Anthropological Association and members of US Commission on Civil Rights. In 1997, OMB issued a Federal Register notice regarding revisions to the standards for the classification of federal data on race and ethnicity. OMB developed race and ethnic standards in order to provide "consistent data on race and ethnicity throughout the Federal Government; the development of the data standards stem in large measure from new responsibilities to enforce civil rights laws." Among the changes, OMB issued the instruction to "mark one or more races" after noting evidence of increasing numbers of interracial children and wanting to capture the diversity in a measurable way and having received requests by people who wanted to be able to acknowledge their or their children's full ancestry rather than identifying with only one group. Prior to this decision, the Census and other government data collections asked people to report only one race.
The OMB states, "many federal programs are put into effect based on the race data obtained from the decennial census. Race data are critical for the basic research behind many policy decisions. States require these data to meet legislative redistricting requirements; the data are needed to monitor compliance with the Voting Rights Act by local jurisdictions". "Data on ethnic groups are important for putting into effect a number of federal statutes. Data on Ethnic Groups are needed by local governments to run programs and meet legislative requirements." The 1790 United States Census was the first census in the history of the United States. The population of the United States was recorded as 3,929,214 as of Census Day, August 2, 1790, as mandated by Article I, Section 2 of the United States Constitution and applicable laws."The law required that every household be visited, that completed census schedules be posted in'two of the most public places within, there to remain for the inspection of all concerned...' and that'the aggregate amount of each description of persons' for every district be transmitted to the president."
This law along with U. S. marshals were responsible for governing the census. One third of the original census data has been lost or destroyed since documentation; the data was lost in 1790–1830 time period and included data from: Connecticut, Maryland, New Hampshire, New York, North Carolina, Rhode Island, South Carolina, Delaware, New Jersey, Virginia. Census data included the name of the head of the family and categorized inhabitants as follows: free white males at least 16 years of age, free white males under 16 years of age, free white females, all other free persons, slaves. Thomas Jefferson the Secretary of State, directed marshals to collect data from all thirteen states, from the Southwest Territory; the census was not conducted in Vermont until 1791, after that state's admission to the Union as the 14th state on March 4 of that year. There was some doubt surrounding the numbers, President George Washington and Thomas Jefferson maintained the population was undercounted; the potential reasons Washington and Jefferson may have thought this could be refusal to participate, poor public transportation and roads, spread out population, restraints of current technology.
No microdata from the 1790 population census is available, but aggregate data for small areas and their compatible cartographic boundary files, can be downloaded from the National Historical Geographic Information System. In 1800 and 1810, the age question regarding free white males was more detailed; the 1820