Unit 1: What is Geography? Part 2: Mapping the Earths
Surface
Slide 2
The Earth is called an oblate spheroid. T he most accurate way
to depict the earth is as a globe, a round scale model of the
earth. A globe gives a true picture of the continents relative
sizes and the shapes of landmasses and bodies of water. Globes
accurately represent distance and direction. Lines of latitude are
called parallels. The equator is defined a zero degrees latitude.
Latitude is the angular distance measured in degrees north and
south parallel to the equator.
Slide 3
The Earth as an Oblate Spheroid
Slide 4
Lines of longitude are called meridians. The prime meridian is
defined as zero degrees longitude. Longitude is the angular
distance measured in degrees east or west of the prime meridian.
The Earth is divided into 4 major hemispheres (you will learn about
spheres as layers of the Earth later). They are the Northern
Hemisphere, the Southern Hemisphere, the Eastern Hemisphere, and
the Western Hemisphere.
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The Major Hemispheres of the Earth
Slide 6
Lines of Latitude
Slide 7
Lines of Longitude
Slide 8
A map is a drawing or other representation, usually on a flat
surface, of all or part of the earth's surface, ordinarily showing
countries, bodies of water, cities, mountains, etc. Cartography is
the science, or technology, of mapmaking. In order to create
accurate maps, one must understand the spherical aspect of the
Earth. The Earths circumference is approximately 25,000 miles! The
diameter around the equator is 7,926.28 miles. The diameter from
the North Pole to the South Pole is 7,899.80 miles.
Slide 9
There are many different types of maps and map projections. The
reason for this is rather simplethe Earth is round not flat! To
fill in the gaps, mapmakers stretch parts of the earth. They choose
to show either the correct shapes of places or their correct sizes.
Most cartographers use software programs called Geographic
Information Systems (GIS). A Global Positioning System (GPS) helps
mapmakers and consumers locate places based on coordinates
broadcast by satellites.
Slide 10
Common Map Projections
Slide 11
Slide 12
The Mercator projection shows true direction and land shapes
fairly accurately, but not size or distance. Areas that are located
far from the Equator are quite distorted on this projection.
Slide 13
Map Interpretation In order for you to fully read and interpret
a map, the map must contain key elements before you can
successfully understand what the map is trying to communicate to
you. Maps have legends. Here, cartographers create the map key
where symbols and colors are used to represent various geographic
data including elevation, population, precipitation totals, infant
mortality rates, etc. The possibilities are endless!
Slide 14
Map Legend (Key) Examples
Slide 15
Cartographers are now using computers and computer programs
called Geographic information systems (GIS). Remote sensing is the
small- or large-scale acquisition of information of an object or
phenomenon, by the use of either recording or real- time sensing
device(s) that are wireless, or not in physical or intimate contact
with the object (such as by way of aircraft, spacecraft, satellite,
buoy, or ship).