Human Geography test 2

Census

Originally, it refers to enumeration and registration of people, property, and taxation.

In modern days, it refers a survey of population in a given geographic region.

It shows dramatic socioeconomic changes over the past century.

Charting and analyzing these changes in cities and regions 

American community survey (ACS)

Filling the gap between the 10-year census

It allows communities to see how they are changing

It helps communities determine where to locate services and allocate resources

1-Year Estimates– 5-Year Estimate

Census and GIS

1990 Census

• Connection between numeric data and geographic data

• User friendly file formats provided

• GIS makes the data acquisition and analysis much faster and more effective 

The capabilities of GIS/Spatial Analysis

enrich our understanding of the number in census files, such as:

– Identify spatial clusters and spatial patterns

– Site selection based on population distribution 

Census aggregation

summed or averaged for a particular geographic area

– Summary level: data at a specific level of geographic aggregation

• Government units: states, counties, cities, villages, towns

• Statistical units: census divisions, census regions, metropolitan areas, urbanized areas, tracts, block groups, blocks 

Census Hierarchy

Federal Information Processing Standards codes (FIPS codes)

• A standardized set of numeric or alphabetic codes to ensure the uniform identification of geographic entities– State, County, Tract, Block Group, Block

State, County, Tract, Block Group, Block

State (2 digits)

• County (3 digits)

• Tract (6 digits): range from 1,500 to 8,000 people with optimized size of 4,000

– A statistical subdivision of a county

– Do not cross county or state lines

– Block groups with similar demographic and economic characteristics and living conditions assembled

• Block group (1 digit): range from 600 to 3,000 people

– The next level above census block in the geographic hierarchy

– A collection of one or more blocks

• Block(3 digits): about 85 people

– The smallest geographic area for which the Census Bureau collects and tabulates decennial census data

– Formed by streets, roads, railroads, streams and water bodies, and other visible physical and cultural features 

Urban areas

– Defined after each decennial census

– 50,000 or more people

– Urban cluster: 2,500 to 50,000 people

Metropolitan Statistical Area (MSA)

Contains major urban area with 50,000 or more population

– Its own county and surrounding counties with heavy commuting patterns

Symbols

the graphic elements of a map

• Symbols often look like the objects they represent

• Symbolizing: assigning colors, markers, sizes, widths, angles, patterns, transparency and other properties to the map display

• Symbolizing is based on values in the data attribute table (e.g. symbolizing categorical attributes)

Classification

• Goal of classification– Putting objects into groups, each group is called a class or a category

– Variation within groups is smaller; Variation between groups is larger

Examples of classification methods in ArcGIS– Manual:

set classes manually

Examples of classification methods in ArcGIS–Equal Interval

range is equally divided

Examples of classification methods in ArcGIS–Defined Interval

define the interval size

Examples of classification methods in ArcGIS–Quantile (Equal Frequency):

same number of objects in each class

Examples of classification methods in ArcGIS–Natural Breaks:

natural grouping inherent in the data

Examples of classification methods in ArcGIS–Geometric Interval:

logarithmic distribution

Examples of classification methods in ArcGIS–Standard deviation:

normal distribution

Thematic Maps of Population Distribution Graduated-

-color map

Proportional-symbol map

Chart map

Dot density map

Choropleth Map

A thematic map in which ranked classes of certain variable are depicted with shading patterns or colors for predefined zones. Graduated-color map is a typical Choropleth map. 

Map Classification:

put map objects into groups (based on different criteria), each group is called a class or a category

Map Classification: Equal Interval:

range of values equally divided (mapping percentage, temperature, precipitation, elevation, etc.)

Map Classification: Equal Frequency:

equal number of objects (the resulting maps can often misleading)

Map Classification: Natural Break:

natural groupings inherent in values (the resulting map may best characterize spatial variations and spatial patterns

Natural landscape–

he array of landforms that configurate the Earth’s surface, such as mountains, hills, plains, plateaus etc.

– Also including the physical features that mark them, such as waters, soils, vegetation, etc

Isoline

A technique to portray the geographic phenomena

– A line connecting points of equal value 

Contour Line:

Equal Elevation

Topographic Map:

using contour lines to represent land relief and the surface configuration of Earth  

Land Relief:

Difference in Elevation (height of land

Spatial Interpolation

A procedure of predicting values at unknown locations from measurements at sampled locations

– Used to convert data from point observations to continuous surface 

Topographic Profile-

A diagram that shows elevation change in the landscape along a line; like a skyline of land relief 

Vertical Exaggeration

= Horizontal Scale / Vertical Scale

Cultural Landscape

It is a combination of nature and culture, and provides some of best evidences of human-environmental interactions

- Carl Sauer, 1925

“The cultural landscape is fashioned from a natural landscape by a cultural group. Culture is the agent, the natural area is the medium, the cultural landscape is the result”

Cultural Landscape

the everyday landscape: farms, gardens, suburbs, trailer parks, shopping malls, and many more, can provide important insights into a culture’s attitudes and way of life. They can be read and interpreted

– National and regional cultural identities remain embedded in urban and rural landscapes. Certain landmarks and landscapes take on special significance in the identity, emotions, and politics of a country

– Landmarks come to symbolize a city in the mental imagery of residents and tourists alike. London’s Big Ben, Paris’s Eiffel Tower, New York’s Statue of Liberty, Sydney’s Opera House are all examples of symbolic landmark 

Land Survey Systems-

Metes and Bounds Rectangular Survey

Metes and Bounds system–

Describe property boundaries using landforms or water features or such landscape elements as prominent trees, unusual rocks, etc.

– It may lead to boundary uncertainty and dispute

– It is related to the topographic road patterns, that roads are controlled by the contours of the land 

Public Land Survey System (PLSS)

rectangular survey system in the Land Ordinance of 1785

– Township and Range survey lines oriented in the cardinal directions

– Land was divided into many regular townships, and each township is 6 square miles

– Each township was further subdivided in to 36 sections, and each section is 1 square mile

Land use:

it refers to how land is being utilized and modified by humans

Land cover

it refers to the biophysical materials found on the land surface

– For example, a national park may be used for recreation, but it is covered by forest. In this case, land use is recreation, land cover is forest 

Conversion

The total transformation of land from one to another– e.g. conversion of forest land to urban settlement 

Modification

An alternation of existing land use– e.g. building roads in forest land 

World Biomes

Urbanization

It is the creation and growth of urban and suburban areas

– It is a transformation from natural landscape to urban impervious land

– Urbanization is one of the most extreme types of land use change

– It is measured as the percentage of the people in a country or in the world living in such areas

Urban growth

It is the rate of increase of urban population

– There are two ways of urban growth

• Natural growth (more births than deaths)

• Immigration from rural areas and other places 

Approximately 6000 years ago, the world’s first cities emerged, Rome is the first city which reached a population of 1 million in 133 BC 

About one half of the world population live in the cities and densely populated areas 

Urban sprawl

Urban areas tend to sprawl outward to the surrounding countryside

– It is the growth of low density development at the edges of cities and towns

– Many people prefer living in sprawling suburbs and exurbs

– As sprawl continues, metropolitan areas join one another to form megalopolis 

The process of urbanization has significant environmental impacts

Urbanization may intensify the Urban Heat Island effect (temperature in the urban area is higher than its surrounding suburban/rural area)

– The increasing impervious surface from urbanization may increase the likelihood of urban flooding

– The increasing impervious surface may exacerbate the non-point source water pollution 

Urbanization and landscape fragmentation

• Landscape fragmentation– Caused by transportation infrastructure and built-up areas

– The ecological effects include the decline and loss of wildlife populations, such as

• prevent access to resources • reduce habitat area and quality • Isolate animal populations 

Effective mesh size–

The probability of chance that two points chosen in a certain region are connected

– Multiplying this probability by the total area of the region to get “effective mesh size”

– The more barriers (roads) in the landscape, the lower the chance that two points are connected, and lower the “effective mesh size”

Forests - Deforestation–

The permanent clearing and destruction of forests

– Loss of biodiversity in an ecosystem

– Destabilization of the oxygen and carbon dioxide cycles of the forests may have long-term effects on global climate

Grassland

Arid or semiarid regions that are unsuitable for farming

– Rainy regions where tropical rain forests are removed

– Mid-latitude prairies

Grassland Desertification: the spread of desert conditions to existing grassland 

Wetland–

Shore areas of lakes, rivers, oceans, and other water bodies

– Wetland degradation 

Hydrological cycle-

the movement of water on, above, and below the surface of Earth, with a changing state among liquid, vapor and ice, which is driven by solar energy and gravity.

• Hydrological cycle helps to collect and recycle the fresh water continuously

• Human activities can gradually impact the water resources in a negative way

Drainage basin (Watershed)–

Streams come together and form stream systems, they are further organized into areas or regions called drainage basins or watershed

– A drainage basin is the spatial unit occupied by a stream system. It is defined by ridges that form drainage divides (e.g. mountain, highland) 

Continental Divides:

Extensive mountain and highland regions that separate drainage basins

Water pollution

is any change in water quality that has a harmful effect

• Leading causes of water pollution– Agricultural activities • Sediment eroded from land • Fertilizers and pesticides • Bacteria from livestock and food processing wastes

– Industrial facilities

– Mining 

• Point source pollution

– Located at specific places, through drain pipes, ditches, or sewer lines into bodies of surface water

– Easy to identify, monitor, and regulate 

Non-point source pollution (NPS)–

Pollutants carried by running water

– Broad, scattered, and diffuse areas

– Difficult to identify and control

– Expensive to clean up 

Non-point source (NPS) water pollution can be exacerbated by the increase of impervious surfaces 

Dissolved Oxygen (DO)

– Human activities can overload water bodies with plant nutrients (e.g. nitrogen and phosphorous) that reduce dissolved oxygen (DO) and kill some aquatic species

– Nutrient enrichment of water bodies is called eutrophication

– The accelerating of eutrophication by human activities is called cultural eutrophication 

Groundwater over-pumping

Contamination of groundwated

Land Subsidence

subside or sink of the land

Karst topography

Topography that results from underground dissolution

Typical karst landforms

– Sinkholes

– Disrupted surface drainage

– Underground drainage networks 

Disappearing steams:

surface runoff disappears into a sinkhole or joint crack

Swallow hole:

the distinct opening at the bottom of some sinks through which surface drainage can pour directly into an underground channel

Overfishing–

Fishprint: a measure of actual fish harvest in an area

– Biocapacity: the ability to provide a sustainable supply of fish year after year in an area 

Tropical Cyclones  

• Originate within tropical air masses

• Between tropic of cancer and tropic of Capricorn

• Powerful cyclones are classified as hurricanes, typhoons and cyclones

Hurricane

• Prominent low pressure center

• Steep pressure gradient and strong winds spiral inward

• Converging wind patterns pulls in warm and moist air, counterclockwise spinning in northern hemisphere

• Air rises in intense updrafts with cumulonimbus clouds

Eye of a hurricane

Eye: the center of a hurricane without storm; diameter is about 10-25 miles; winds do not converge to the eye

– Eye wall: winds reaches their highest speed at eye wall; bands of dense cumulus and cumulonimbus clouds; heavy rain 

Hurricane Tracks

– Irregular tracks within the general flow of trade winds

– Typically moving from east to west; some begin on an east west path, and then curve toward the north

• Life span– Do not last long– Average is about a week

tropical cyclonic system

Convergent lifting

mid-latitude cyclonic system

Frontal lifting

Thunderstorms

Violent convectivestorms

Usually localized and short lived

Vertical air motion, considerable humidity and instability

Occurs as individual clouds, produced by thermal convection

Accompanied by thunder and lightning

Formation stages: Cumulus stage ’ Mature stage ’ Dissipating stage 

Tornadoes

A spinning, cyclonic, rising column of air forms a mesocyclone, a mesocyclone rotates vertically to a height of thousands of meters, producing heavy rain, hail, winds and lightning

’ The narrower the mesocyclone, the faster the spin of air

’ The mesocyclone itself is visible dark gray funnel clouds. The lowering of a funnel clouds to Earth is a tornado

’ A tornado can range from a few meters to a few hundred meters in diameter

Decennial Census vs. ACS:

The Decennial Census occurs every 10 years and is a count of the total population for representation. The American Community Survey (ACS) is ongoing and provides detailed social and economic data.

GIS Integration:

The 1990 Census was the first to fully incorporate Geographic Information Systems (GIS).

Census Hierarchy (FIPS):

The spatial extent flows from largest to smallest: State → County → Tract → Block Group → Block.

Land Use vs. Land Cover:

• Conversion: Changing land from one use to another (e.g., forest to farm).

• Modification: Changing the condition of the land without changing the category

Urbanization Impacts:

• Urban Growth vs. Sprawl: Sprawl is the rapid, often poorly planned spread of cities.

• Urban Heat Island: Cities are warmer than surrounding rural areas due to concrete and asphalt.

• Landscape Fragmentation: Breaking up habitats, measured by Effective Mesh Size.

Water Table:

The upper level of the underground zone of saturation.

• Pollution Sources:

• Point Source: Identifiable pipes or ditches (e.g., a factory drain). Easy to regulate.

• Non-Point Source (NPS): Broad, diffuse areas (e.g., agricultural runoff). Difficult and expensive to control.

Eutrophication:

Nutrient enrichment (Nitrogen/Phosphorus) leading to algal blooms and reduced Dissolved Oxygen (DO).

Groundwater Issues:

Over-pumping leads to Land Subsidence (sinking) and saltwater contamination.

Karst Topography

Landscape formed from the dissolution of soluble rocks like limestone.

Features:

• Sinkholes: Depressions caused by collapsing underground caverns.

• Disappearing Streams: Surface water that flows into a sinkhole or crack.

• Swallow Hole: The specific opening at the bottom of a sink where water enters an underground channel.

Tropical Cyclones:

Called Hurricanes (Atlantic/N. Pacific), Typhoons (NW Pacific), or Cyclones (Indian Ocean).

Structure: The Eye is calm with low pressure; the Eye Wall has the strongest winds and heaviest rain.

Movement: Usually move East to West in trade winds, then curve North.

Tornadoes:

Form from a rotating Mesocyclone. The narrower the mesocyclone, the faster the wind speed.

Thunderstorms:

Three stages: Cumulus, Mature (most violent), and Dissipating.

Koppen Classification:

A system categorizing climates based on temperature and precipitation (e.g., Type A = Tropical).

Overfishing:

* Fishprint: The area of ocean needed to sustain a person/population’s fish consumption.

• Biocapacity: The ability of an area to provide a sustainable supply of fish.

• Aral Sea: A prime example of environmental disaster caused by diverting water for irrigation, leading to massive shrinkage.

Grid pattern

eg. new york city

radial pattern

eg. Paris

Star pattern

eg. Tokyo

Linear Pattern

eg. Brasilia