MODIS Natural Color10/11/00

Essentials of GeographyDanny M. Vaughn, Ph.D., CMS

Essentials of Geography

• The Science of Geography.  • Earth Systems Concepts.  • Location and Time on Earth.  • Maps, Scales, and Projections. 

• Remote Sensing and GIS.  

The Science of Geography

• Geography – from geo “Earth” and graphein “to write.” 

• Geography is –– A method, not a body of knowledge.– Holistic.– Eclectic.

• Geographers use spatial analysis.• Geographers use Earth systems science.

Geography is –• The science that studies the relationships among – Natural systems. – Geographic areas.– Society. – Cultural activities.– Interdependence of all of these

over space.

Geographic Science is –

• Location – Where are the spatial objects?• Place – Tangible & untangible living/nonliving characteristics.

• Central Park, N.Y.• Region – Uniform physical characteristics.

• Colorado Plateau.• Human-Earth Relationships – How does each impact the other?

• Desert SW & Navajo Americans lifestyle.• Movement – Energy exchanges, physical/human movement.

• Winds, ocean currents, human relocation.

Physical Geography is –

• The spatial analysis of all the physical elements and processes that make up the environment.

Process – actions resulting in a change.Governed by – physical, biological, chemical laws.

Climate Weather EnvironmentEnergy Air WaterLandforms Soils PlantsAnimals

• Geographers use the scientific method.

Earth Systems Concepts

• System – ordered, interrelated objects functioning as a unit. 

• Open systems – energy & matter flow into & out of the system.

• Closed systems – energy flows in & out of the system.

Systems

• Positive feedback – encourages system response, higher discharge, more sediment transported.• Negative feedback – more volcanism, cooled temperatures.• System Equilibrium – a maintenance of structure over time through energy-material exchanges.

Earth’s Four Spheres

•Atmosphere•Hydrosphere•Lithosphere•Biosphere

Earth Shape • Oblate Ellipsoid – flattened at the poles, bulging at the equator. • Greater centrifugal force at the equator (faster rotation).

• Geoid – sea level surface in balance between gravitational attraction & centrifugal pull due to rotation.

Earth’s dimensions

Measuring Earth in 247 B.C.

Location and Time on Earth  

• Latitude.• Longitude.• Great circles.• Prime Meridian and standard time.

Latitude

Longitude

Great Circles and Small Circles

Latitudinal Geographic Zones

• Greenwich Mean Time – World standard (UT) time. Longitude (prime meridian) established by International Meridian Conference, Washington, D.C., 1884.

• Universal Time Coordinated (UTC) – standardized by French in 1912, determined by the International Bureau of Weights & Measures (Paris).

• Daylight savings time – Spring forward (lengthens daylight time), fall back.

International Date Line –

West crossing – one day ahead.East crossing – one day behind.

Prime Meridian and Standard Time  

Maps, Scales, and Projections  

• Map – a generalized view of an area, as seen from above and reduced in size.

Cartography – map making.

• Scale – ratio of map units to ground units.Descriptive, graphic, & representative fraction.

• Projection – process of transforming spherical Earth to flat map. • Earth can not be projected without distortion of its:Shape, area, distance, &/or direction.

Properties of the spherical (Earth) graticule –  • Latitudes are parallel, evenly spaced along meridians (longitudes), & decrease in length poleward.

• Meridians converge at the poles & decrease in length to a point at the poles.

• Parallels & meridians intersect at 90º.

Classes of Projections

Remote Sensing• Active remote sensing.• Passive remote sensing.

Active and Passive Remote Sensing

Passive sensingvisible light.

Active sensingRADAR.

Remote Sensing

• MODIS sensor on board a TERRASatellite, June, 2001.

Geographic Information Systems (GIS) 

• GIS systems combine spatial and attribute data. 

• Maps can contain multiple data layers:– Physical features.– Cultural features.

• Layers can be added to create composite overlay.

GIS System