Contemporary Tools

Contemporary Tools:• Geographic Information System (GIS)• Remote Sensing• Global Positioning System (GPS)

Layers of a GISContemporary tools like Geographic Information Systems (GIS) store information about a location in several layers. Each layer represents a different category of information which can be used to illustrate relationships between categories.

Remote Sensing• Remote sensing is the acquisition of data

about Earth’s surface from a satellite orbiting Earth or from other long-distance methods. Maps created by remote sensing are essentially a grid containing many rows of pixels. Objects as little as one meter can be sensed by remote. Other than environmental applications, human geographers map urban sprawl and agricultural practices.

Global Positioning Satellite (GPS)

• GPS is a system that determines accurately the precise position of something on Earth. GPS is most commonly used in navigation of aircraft and ships. Geographers use GPS to code locations for objects that can later be combined in images for GIS.

Place and Location• Place is a geographic concept that accounts for the sense

of uniqueness about a particular location. Describing the unique features of a place is essential to Geography.– Toponyms are the names given to Places and they help

to describe the place.– Site is the Physical character of a location like climate,

water, topography, soil, vegetation, latitude and elevation, which helps to describe the place.

– Situation is the location of a place relative to another feature, which helps to describe its location. Example: Louisville is on the Ohio River.

• Location can be described precisely using the grid of latitude and longitude.

Toponym

“Louisville” is a toponym that reflects the importance of the role the French played in helping the colonists defeat England in the American Revolution.

“St. Matthews” is a toponym that reflects the French Catholic influence on the region. (Catholicism is the branch of Christianity that emphasizes the use of “saints”.)

Site: Lower Manhattan Island

Lower Manhattan Island, New York City is located on the Hudson and East Rivers, at sea level, and 40˚ North Latitude. There have been many changes to the area over the last 200 years.

Situation: Singapore

Singapore is located in Southeast Asia at the tip of Malaysia. It is also located on the Singapore Strait north of Indonesia. At that point, it is situated at a key location for international trade.

World Geographic Grid

The world geographic grid consists of meridians of longitude and parallels of latitude. The prime meridian (0º) passes through Greenwich, England. The International Date Line is at 180˚ Longitude. The Equator is at 0˚ latitude.

World Time Zones

The world’s 24 standard time zones are often depicted using the Mercator projection. Earth is divided into 360˚ of longitude. Every 15˚ of longitude equals 1 hour of time (and one time zone) which equals 24 time zones. New York is 5 hrs behind Greenwich Mean Time (GMT). The Central Time zone is 6 hrs behind GMT, Mountain is 7 hrs behind, and Pacific is 8 hrs behind GMT. If it’s 7pm in London, it’s 2pm in New York. What time would it be in Chicago? Denver? Los Angeles?

U.S. Land Ordinance of 1785 In the U.S., the Land Ordinance of 1785 divided the country into a system of townships and ranges to facilitate the sale of land to settlers across the west. North-south Principal Meridians and east-west Baselines create the township system. A township is 6 square miles. Townships in the first row north of a baseline are called T1N. The first row south is called T1S. Townships east of the principal meridian are designated R1E. Townships west are designated R1W. A townships is divided into 36 sections each 1 mile square. A quarter section is 160, and was the common size of a pioneer farm.

Diffusion• Diffusion is the process of spread of a feature or

trend from one place to another over time. – Hearth is where something originates.– Relocation Diffusion is the spread of a feature or trend

through bodily movement of people from one place to another.

– Expansion Diffusion is the spread of a feature or trend among people from one area to another in a snowballing process.

• Hierarchical Diffusion is the spread of a feature or trend from one key person or node of authority or power to other persons or places.

• Contagious Diffusion is the rapid, widespread diffusion of a feature or trend throughout a population.

• Stimulus Diffusion is the spread of an underlying principle, even though a specific characteristic is rejected.

AIDS: Relocation Diffusion 1981–2001

New AIDS cases were concentrated in three nodes in 1981. Through relocation diffusion, they spread through the country in the 1980s, but declined in the original nodes in the late 1990s.

Expansion Diffusion: Hierarchical

Hierarchical Diffusion is the spread of a feature or trend from one key person or node of authority or power to other persons or places. Music and entertainment often diffuse hierarchically from Hollywood and Los Angeles, California.

Expansion Diffusion: Contagious

Similar to a disease like Influenza and a wave at a sporting event, indiscriminate of social rank, contagious diffusion spreads amongst the people.

Expansion Diffusion: Stimulus

The diffusion of the “mouse” concept originated with Apple computers, but was incorporated into IBM’s Windows operating system as it diffused across the globe and it became the normal way of operating your computer.

Density, Concentration, and

Pattern

Fig. 1-18: The density, concentration, and pattern (of houses in this example) may each vary in an area or landscape.

Distribution is the arrangement of something across Earth’s surface.

• Density is the frequency with which something exists within a given unit of area.– Arithmetic density is the total number of people

divided by land area.– Physiological density is the number of people

per unit area of agricultural land.– Agricultural density is the ratio of the number of

farmers to the total amount of land suitable for agriculture.

Distribution Continued

Distribution Continued• Concentration is the spread of something

over a given area.– Clustered is close together.– Dispersed is spread out.

• Pattern-– Geometric patterns are primarily linear or

circular.– Irregular patterns don’t have a detectable pattern.

Density and Concentration of Baseball Teams, 1952–2000

The arithmetic density of baseball teams changed from 16 in 1952 to 30 in 2000. Concentration changed from a cluster in the Midwest and Northeast to a dispersed arrangement across the U.S.

Distribution Continued

The roads at right lend themselves to linear and circular patterns, but often patterns won’t be overly clear.