Unit 2 Flashcards
Ancient Greek philosophers
– Spherical shape
• 350 BCE
Eratosthenes
– Accurately estimated Earth’s
circumference
• 200 BCE
Ellipsoid Earth
– Similar to a sphere, but with a bulge around the center (Equator) • Earth is not a perfect “Ellipsoid” – Rugged terrain • Mt. Everest (8.8 km above sea level) • Marianas Trench (10.9 km below sea level)
spheres of the earth
- Atmosphere
- Lithosphere
- Hydrosphere
- Cryosphere
- Biosphere
- Hemisphere
Atmosphere
– Blanket of air that adheres to the Earth’s surface – Ranges from a few meters below the surface to 60,000 km (37,000 mi) – In continuous motion due to solar energy
Lithosphere
– Outermost shell of the solid Earth – Forms Earth’s scenery • Mountains • Valleys • Seafloor
Hydrosphere
– All of the liquid water on the
Earth’s surface and in the
atmosphere
– 71% of the Earth’s surface
Cryosphere
– All of the frozen water including
glaciers, floating ice, snow cover,
and permafrost
Biosphere
– Zone of life
– Includes vegetation and animals
Hemisphere
– Hemi –meaning half
– Sphaira –meaning sphere
equator
Imaginary line that circles the earth at zero degrees latitude
prime meridian
– Imaginary line that runs from the North Pole to the South Pole and passes through Greenwich, England
international date line
– Imaginary line that runs from the North Pole to the South Pole and passes through the Pacific Ocean
northern hemisphere
– From Equator to the North Pole
– 70% of Earth’s land area
southern hemisphere
– From Equator to the South Pole
– Dominated by water
western hemisphere
– Extends from the Prime Meridian
westward to the International
Date Line
eastern hemisphere
– Extends from the Prime Meridian
eastward to the International
Date Line
cartography
– The science, art, and
technology of mapmaking and
map use
Location
– A grid is formed on the Earth’s surface as lines run both E-W and N-S •Lines form great circles and small circles
great circle
– Plane that passes through the center of a sphere dividing it in half – Represents the circumference of a sphere – Ex: Circle of Illumination
small circle
– Plane that passes through any other
part of a sphere than the center
– Ex: Tropic of Cancer
lines of latitude
– Run E-W around the Earth
•Measure N/S component of a
location
lines of longitude
– Run N-S around the Earth
•Measure E/W component of a
location
conversion equations
– To convert from minutes and seconds to decimal form:
•Divide seconds by 3,600 and divide minutes by 60 and add the two
– To convert from decimal to degrees and seconds:
•Multiply decimal by 60. Whole number is minutes. Multiply the remaining
decimal by 60. That is the number of seconds
elevation
– Height above some reference value (i.e. vertical datum) – Distance above mean sea level (AMSL) • Use average to eliminate tidal and other effects
GPS
– Easy way to determine location
– Relies on a network of 24 satellites,
which are in geosynchronous orbit
– Uses signals from these satellites
Map Projections
– Project Earth and its “lines” onto a surface to create a 2D map
•Will be errors!
conformal
– Map projection that preserves the true shape
– Area is not preserved
-mercator
equal area
– Map projection that preserves the true area
– Shape is not preserved
-peters
cylindrical map projections
•Transfer of Earth’s latitude and longitude grid from a globe to a cylinder •Ex: Mercator Projection – Most popular cylindrical projection – Any straight line is a line of true and straight compass bearing
conic map projection
– Conic •Transfer of Earth’s latitude and longitude grid from a globe to a cone •Typically used in mid-latitudes that cover a large expansion of longitudes
Standard parallel
– The line of latitude where the projection surface touches the globe – Found in conic or cylindrical projections •Tangent: 1 standard parallel •Secant: 2 standard parallels
planar map projections
– Planar
•Imaginary plane that touches
the globe at a single point
•Typically used for polar regions
mathematical map projections
•No projection surface
•Minimize distortion
– Devote most of the projection to the parts that project best
– Deemphasize areas of the globe that are not essentia
scale
– Ratio of map distance to Earth
distance
– Should always be 1:some #
small scale
– Shows large area with less detail (i.e.
world map)
– Large denominator (1:75,000,000)
large scale
– Shows small area with great detail (i.e.
hiking map)
– Small denominator (1:7,500
Isopleth (Isolines)
– Depict surfaces
– “iso” means equal
– Numerous lines that represent
points of equal value
Contouring (contour lines)
– Measure elevation
– Each contour line represents
an elevation value
isotherms
– Measure temperature
– Each line represents a temperature
value
gis
– A grouping of computer software and hardware – Enables spatial data to be collected, analyzed, stored, retrieved, manipulated, and displayed – A lot of spatial data collected using remote sensing techniques – “Interactive Mapping
remote sensing
– Ability to scan the Earth from airborne and satellite observation platforms to gain information •Examples: – Elevation – Cloud cover – Vegetation – Infrastructure
