Learning to read and understand maps is an important skill!
Geographers and cartographers organize locations on the earth using a series of imaginary lines that encircle the globe. Lines of latitude and longitude were created to accurately locate places on the earth.
Latitude lines go round and round.
Longitude lines go up and down.
Put them together to locate your town!
Latitude lines are kind of like hula hoops stacked on each other that get smaller the closer they are to the poles. Think of the equator as the biggest hula hoop and the last line of latitude near the north (or south) pole as a little hula hoop.
Latitude and longitude are measured in degrees, which is marked by this symbol: °. The equator is 0° latitude because it goes around the middle of the earth like a belt between the Northern and Southern Hemispheres. Every line of latitude above the equator is marked with an N for north. Every line of latitude below the equator is marked with an S for south. There are 180 lines of latitude: 90 lines are north of the equator and 90 lines are south of the equator.
Latitude lines are also known as parallels because they are parallel to each other.
There are 5 important lines of latitude. They are the Arctic Circle, the Tropic of Cancer, the equator, the Tropic of Capricorn and the Antarctic Circle.
The area between the Tropic of Cancer and the Tropic of Capricorn is known as the tropics. This area doesn’t experience four seasons as it receives about the same amount of sunlight all year long. This area is usually very warm, except at very high elevations.
Longitude lines are kind of like sections of an orange from the top to the bottom. Longitude has a pretend starting line, too, just like latitude has the equator. This line is called the Prime Meridian, which starts at the North Pole, cuts through Greenwich, England, goes through part of Africa and ends at the South Pole. The Prime Meridian is 0° longitude. Longitude lines do not go completely around the globe. They start at the top and end at the bottom. There are 360 lines of longitude. 180 lines to the east of the Prime Meridian are marked with an E for east. 180 lines to the west of the Prime Meridian are marked with a W for west.
If you know the latitude and longitude coordinates of any spot on earth, you can use a high-tech system called GPS (global positioning system) to get you there.
The meridian at 180 degrees is called the International Date Line. The International Date Line is opposite the prime meridian and indicates the start of each day (Monday, Tuesday, etc.). Each day officially starts at 12:01 a.m., at the International Date Line. The actual International Date Line does not follow the 180-degree meridian exactly. A number of alterations have been made to the International Date Line to accommodate political agreements to include an island or country on one side of the line or another.
Universal Time (UT), Coordinated Universal Time (UTC), Greenwich Mean Time (GMT), or Zulu Time (Z): all four terms can be defined as local time at 0 degrees longitude, which is the prime meridian (location of Greenwich, England). This is the same time under which many military operations, international radio broadcasts, and air traffic control systems operate worldwide. UTC is set in zero- to twenty-four-hour time periods, as opposed to two twelve-hour time periods (a.m. and p.m.). The designations of a.m. and p.m. are relative to the central meridian: a.m. refers to ante meridiem, or “before noon,” and p.m. refers to post meridiem, or “after noon.” UT, UTC, GMT, and Z all refer to the same twenty-four-hour time system that assists in unifying a common time in regard to global operations. For example, all air flights use the twenty-four-hour time system so the pilots can coordinate flights across time zones and around the world.
Now that we know how to find a location on a map, let’s talk about maps themselves. Maps are flat representations of a spherical earth and are called projections. It’s impossible to create a perfect map projection. Let’s take a look at that!
There are many different map projections. This SciShow video explains some of the different projections and their advantages and disadvantages:
Features on a map are represented by symbols, signs, and colors. There is sometimes a map key (also known as a legend) to explain specific items on a map like roads, buildings, etc. There are also maps that show elevation and other physical features. Take a look at the topographic map below. The map illustrates the two mountains on the island of Hawaii.
You’ll be looking at and memorizing a lot of different maps this year! By the end of the year you will (hopefully) NOT be like the following people in this video:
✎ Latitude and longitude are imaginary lines on the globe that help us accurately located places on the earth.
✎ There are 5 important lines of latitude. They are the Arctic Circle, the Tropic of Cancer, the equator, the Tropic of Capricorn and the Antarctic Circle.
✎ An important line of longitude is the Prime Meridian.
✎ The International Date Line is opposite the prime meridian and indicates the start of each day.
✎ It’s impossible to make a perfect map projection.
✎ Features on a map are represented by symbols, signs, and colors.
Next: Chapter 2: Antarctica
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Image and additional information credits:
Latitude and longitude globes, important lines of latitude, prime meridian globe:
© Jennifer Guest
International date line map
By user:Jailbird – File:International Date Line.png cropped, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=37991713
Topographic map of Hawaii
By © Sémhur / Wikimedia Commons, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=3897692