Geography 101

Geography

"Geo"-earth; "graphy"-to write about. Geography means "writing about the earth." It's a synthesizing science that borrows information from many different disciplines.

Polarity/Parallelism

...occurs because the earth's polar axis is always pointed in the same direction, towards the North Star or Polaris. Parallelism refers to the fact that at any time during the earth's revolution around the sun, its polar axis is parallel to its orientation at all other times.

If you are half way around the earth , to the west of the Prime Meridian, what is your longitude?

180 degrees

15 degree longitude

360/24 equals to 15 degrees for every one hour on earth

If you are half way between the equator and the North Pole, what is your latitude?

45 degrees N.

If you are one-fourth of the way around the earth to the east of the Prime Meridian, what is your longitude?

90 E

Distance between earth and the sun

93 million miles, plus or minus approximately 1.5 million

Plane projections

Are commonly used to depict the polar regions with the point of tangency at the poles. Gnomonic maps, produced from plane projections have all straight lines drawn on the map as great circles, and therefore represent the shortest distance between any two points on the earth's surface.

Isohyets

Are lines that connect points of equal quantities of precipitation

Isolines

Are lines that connect points of equal value of many different phenomena.

Ending point of latitude

At both the north and the south poles and has the value of 90 degrees N and 90 S, respectively

Environmental spheres

Atmosphere, hydrosphere, biosphere, and lithosphere.

Hydrosphere

Comprises water in all its forms. The oceans contain the vast majority of the water found on earth and are the moisture source for precipitation. Cryosphere-water frozen as snow and ice.

Isobars

Connect points of equal atmospheric pressure

Contour lines

Connect points of equal elevation and are depicted on topographic maps.

Isogonic lines

Connect points of equal magnetic declination

Isotherms

Connect points of equal temperature

What is the term that refers the two numbers that define a location on the earth's surface?

Coordinates

What characteristics are commonly distorted on maps?

Distances, directions, size, and shapes

Velocity of earth's rotation

Divide earth's circumference by the 24 hours 24,900/24=1037.6 mph. Velocity varies according to latitude. Greatest at the equator and decreases to 0 at the poles.

Biosphere

Encompasses all the parts of earth where living organisms can exist

Fractional scale

Expresses map scale in the form of a fraction, with the numerator representing the map distance and the denominator representing the actual distance on earth. They expressed in the same units. Example: "one inch equals 2 miles"- in fractional scale- 1/126,720 or 1:126,720

Globes vs maps

Globes are more accurate, albeit in a smaller scale. Maps are less accurate and distort some info on the earth's surface.

Geographic grid system

Graticule

Aerial photography

Has provided thousands of photos of the earth's surface from airplanes and satellites. Two overlapping aerial photos can be viewed with a stereoscope to "see" the landscape in 3-dimensions

Plane of the ecliptic

Imaginary plane formed by the earth's revolution around the sun

Daylight saving time

In the mid to higher latitudes, the clock is set forward by one hour in the summer months . The 2nd Sunday in March and first Sunday in November. It's not practiced in Hawaii, Arizona, Puerto Rico, the Virgin Islands, Guam and American Samoa

Cultural geography

Includes social science topics such as population, economic activities, language, religions, political system, settlements and food. Transportation, recreation activities, and traditions are also a part of it.

Insolation

Incoming solar radiation. The length of the day and the angle of the sun's rays determine the amount.

Globe

Is a three-dimensional, small scale model of the earth. The dimensions are length, width and height ( or depth)

GIS

Is an acronym for Geographic Information System. It is computerized system used to store, analyze and display spatial data, most commonly in overlay analysis

Circumference

Is approximately 25,000 miles, or more accurately 24,900 miles (40,000 kilometers).

Great circle

Is the largest circle that can be drawn on a sphere. It represents earth's circumference and is formed by a plane passing through the center of the earth. It extends 25,000 miles.the equator is the only parallel that is a great circle.

Radar sensing

Is used to produce an image of the terrain and topography of an area and has the advantages of being able to produce an image at night and through clouds.

Earth's shape

It is an oblate spheroid, resulting from flattening at its polar axis and bulging slightly at the end equator. Equatorial diameter is 42 kilometers. Other name-oblate ellipsoid.

Map projection

It refers to a light projection that transfers the information on a globe onto a surface.

Revolution

It takes 365.25 days to make one complete revolution. It is counterclockwise. It forms an ellipse.

Circle of illumination

It's a great circle that divides the earth into day and night hemispheres. The equator divides the earth into the Northern and Southern Hemispheres. Hawaii is located in the northern and Western Hemisphere

Graphic scale

It's a line divided into segments, each equaling a certain number of miles on the earth's surface. It would s found on the bottom of maps, commonly maps used by travelers providing an easy way of estimating distances.

Map scale

It's a ratio between distances on a map compared to the actual distance on the earth's surface.

Rotation

It's completed in 24 hours, hence one day. It's counterclockwise. It gives the impression that the sun rises in the east and sets in the west.

Universal time coordinated

It's the basis of the standardized time system that uses the local time of the Greenwich meridian as the standard for the rest of the world

Solstice periods

June solstice-June 21 and December solstice - December 21. Sub solar point is located at Tropic of Cancer in June, and during December- Tropic of Capricorn

Large scale map vs small scale map

Large scale maps depict small areas but provide considerable detail and small scale maps depict large areas but with limited detail. That's why world maps are considered small scale and a city map , by comparison, is large scale. When comparing fractional map scales, the larger fractions represent large scale maps and the smaller fractions -small scale maps. Example: the map scale 1/24,000 is a larger scale than 1/120,720

Sub solar point

Latitude on the earth's surface that experiences the perpendicular rays of the sun and is also called the declination of the sun.

Geographic distance

MERIDIANS-vertical lines or lines of longitude; PARALLELS-horizontal lines or lines of latitudes

Dilemma in choosing map projection

Map should show size (equivalent), and shape (conformal) accurately. The Mercator is conformal but distortion of size or area increases towards the poles. If you look at Greenland and it seems like it is bigger than Africa or South America, then you're dealing with a Mercator map. Equivalent projections preserve equal area relationships but disfigure the shapes of land masses.

Advantages of maps

Maps are portable, they provide more specific info, such as street you live on and less expensive to produce.

Meridians

Measure angular distances east and west of the Prime Meridian, which passes through the Royal Observatory in Greenwich , England. It has the value 0 degrees longitude.

Latitude

Parallels measure distances north and south; LATITUDE

Aphelion

Period when the earth is furthest from the sun. July 4th (94.5 million miles away)

Advantages of a globe

Represents accurate spatial relationships of features of the earth. You can view certain parts on the earth's surface that you can't see on the map. The polar zone, including the southern continent of Antarctica is easily viewable on the globe

Cylindrical projections

Result in world maps with the line of tangency located at the equator. Mercator projection is the most famous created in 1560's as an aid to ocean navigation. Straight lines drawn on Mercator maps are lines of constant compass direction called LOXODROMES.

Earth movements

Rotation and Revolution

Thermal infrared

Senses the amount of heat given off by an object and has been widely used to determine land and ocean temperature changes, detecting forest fires, and forecasting the weather

Color infrared technology

Senses the infrared part of the electromagnetic spectrum and can be used to evaluate the health of vegetation, determine the extent of forest dieback, and differentiate between three species.

Sonar technology in the 20th century

Sonar provided an image of the ocean floor that didn't conform to the prevailing view of the ocean floor topography and eventually led to the development of the theory of plate tectonics. It has also led to the development of a modern theory of the evolution of volcanic islands, when catastrophic landslides on the ocean floor around the major Hawaiian islands were revealed

GPS

Stands for Global Positioning System and refers to a satellite based system for determining precise locations on the earth's surface.

Physical geography

Studies natural science phenomena such as landforms, rocks and minerals, water, weather and climate, plants, animals and soil. Flora and fauna is also a part of it.

Equinoxes periods

The March (spring or vernal) March 21. September (autumnal or fall) September 21. The sub solar point is located at the equator

Conic projections

The apex of the cone is usually positioned above the poles so the line of tangency corresponds to a parallel located in the middle latitudes.

The earth's rotation results in

The diurnal changes of night and day; the apparent deflection of winds and ocean currents (Coriolis effect); with the gravitational pull of the moon, causes tidal changes.

Earth's inclination or tilt

The earth is tilted 23.5 degrees away from perpendicular or the polar axis is tilted 66.5 from the plane of the ecliptic. It remains the same throughout the earth's revolution.

Atmosphere

The gaseous envelope of air that surrounds earth. It contains the complex mixture of gases needed to sustain life. Closely to Earth's surface , being densest at sea level and rapidly thinning with increased altitude. Is a very dynamic sphere, kept in almost constant motion by solar energy and earth's rotation.

Longitude distance

The max number of degrees for longitude measurements is 180 degrees. Located at the meridian called the international Date Line, which is on the opposite side of the earth from the Prime Meridian

Perihelion

The period when earth is closest to the sun. It occurs on January 3 and it is 91.5 million miles from the sun

Types of map projections

The plane or planar, conic, and cylindrical.

Proof's of earth's roundness

The result of pliable lithosphere, as a rotating body will develop a slight bulge at its midriff and flatten at the top and bottom. The topographic variations of the earth's surface, created by mountains and valleys are another deviation from a spherical earth.

Lithosphere

The solid, inorganic portion of earth. Litho-stone. It is shaped into an almost infinite variety of landforms, both on the sea floors and on the surfaces of the continents and islands.

Small circles

They represent circles formed when the plane divides a sphere into two unequal halves and does not pass through the center of the earth. All parallels, except equator, are small circles.

Equinox

Translates to equal nights and implies equal length of night and day , or 12 hours of night and 12 hours of a day

Four important parallels

Tropic of Cancer at 23.5 N; Tropic of Capricorn 23.5 S; Arctic Circle at 66.5 N; Antarctic Circle at 66.5 S

Map

Two-dimensional (length & width) representation of phenomena on the earth's surface.

Sonar

Uses sound waves to produce the equivalent image of the ocean floor topography.

Verbal map scale

Uses words to express map scale, such as " one inch equals one mile" meaning, one inch on the map equals one mile on the earth.

Remote sensing

Various methods of obtaining information on the earth's surface from a distance, via satellites, airplanes, weather balloons, and ships. The information can be used to produce maps of many different phenomena or simply provide up to date maps.

Equatorial

Zone within a few degrees of the equator.