MAPWORK

TOPIC ONE

Why do we use maps? Maps are very important tools for geographers because they enable them to

record, display and analyse information about people and the environment

around them.

Maps can be in the form of paper, digital images and also globes.

Aerial photographs are of particular use to geographers and cartographers.

When taken from a relatively low altitude, they are also used to plan towns and

structures, accurately measure roads and rivers, survey the resources of an

area, and show how the physical and cultural features of a place have changed

over time.

Brief history of aerial photography

Since the late 1850’s, people have been trying to see the world as the birds do.

The first two attempts at aerial photography were actually by balloon! The first

was in 1858 when someone flew over Paris. Sadly, the pictures they took are no

longer around. But, in 1860, two men flew over and photographed Boston.

This photograph was called “Boston as the Eagle and the Wild Goose see it”!

Aerial Photograhy

Next, in 1882, a man named E.D. Archibald used a kite instead of a balloon to

take pictures. This proved useful for meteorologists, and others followed his ex-

ample. Still, even newer methods rapidly gained popularity. In 1909, a group of

people mounted a video camera to an airplane! They did it to make a short

movie .

And think about it, how many movies nowadays still do this?

Aerial view of Wall Street in NYC

Aerial photography after WW1

Aerial photography really took off after

World War 1. During the war, people would

use planes to scout enemy territory.

Afterward, air force veterans used these

same skills for more peaceful purposes.

They’d use planes to take and sell pictures,

as people still do today. Although, they’re

now also rivalled by satellite photographers!

Aerial photography nowadays

The most important use of aerial photography is, simply, to keep track of things.

We call this surveillance. Aircrafts survey all sorts of things which may need

repair or protection. The environment is one such thing. Although we also

survey power lines, buildings, and other manmade structures.

Now it’s your turn. Try to guess these landmarks and discuss

your findings.

________________________________

________________________________

________________________________

________________________________

________________________________

________________________________

The lines extending around the Earth horizontally are called lines of latitude.

They measure how far north or south an object is on the Earth. The lines run-

ning vertically around the Earth are called longitude. These lines are also called

meridians, and measure how far east or west an object is.

Longitude & Latitude

As with latitude, longitude is measured as an angular distance. With latitude,

the angular distance is measured from the equator. This is a natural place to

begin.

However, with longitude there is no natural beginning point. One of these lines

must be designated as a prime meridian, or as the 0° mark, but which one?

Where is the official worldwide Prime Meridian?

________________________________

The further away from the Prime Meridian that one travels the higher their

longitude becomes, until they reach 180° longitude. If an individual is in the

Eastern Hemisphere, their longitude is measured in degrees east. If they are in

the Western Hemisphere, their longitude is measured in degrees west.

If you stay in one place, a day lasts 24

hours. However, if you travel the

opposite direction Earth’s rotation,

your day will be slightly longer than 24

hours, because you are traveling

ahead of the setting sun. If you travel

with the rotation of the Earth, your

day will be slightly shorter than 24

hours because you are traveling into

the sunset.

The International Date Line

At any one moment there are actually two days on the Earth at the same time.

A new day begins at midnight on the International Dateline. It travels around

the Earth until 48 hours later it ends back at the International dateline. If you

were to travel across the International Dateline, the date would change either

forward or backward. This line actually lies in the middle of a time zone. This

means that the hour on the clock would not change as you crossed over, just

the date.

A time zone is an area on Earth that has a specific time that all citizens can set

their clocks to.

Different places on Earth have different time zones. They exist because the

Earth is round and they allow everyone to have sunrise and sunset.

You can figure out if another time zone is earlier or later than yours just be

seeing if it is west or east of you on a map.

Timezones

Knowing the time zones is very important for communication. To be able to

identify and calculate time zones, you must know terms like Lines of

Longitude, Prime Meridian and the International Date Line.

What time it is at different places on earth depends on lines of longitude.

These are the imaginary lines that run from the North Pole to the South Pole.

If you slice the Earth evenly across, it would look like a circle.

A full circle is 360 degrees around. These degrees is how we can divide the

Earth into time zones.

The line of longitude labelled 0 deg is the prime meridian.

• Lines to the right of the prime meridian are labelled east;

for example, the line labelled 90 degs E.

• Lines to the left of the prime meridian are labelled west;

for example, the line labelled 90 degs W.

If you travel all the way around the earth in one direction, you would have

travelled 360 degs.

How does this relate to time?

When the earth rotates, we experience day (sunrise) and night (sunset). But

what's really happening is that our position on the earth is facing towards and

then away from the sun.

A full circle rotation of the earth on its axis towards and then away from the sun

equals one day, or 24 hours.

So if 24 hours = 360 degs, how many degs is 1 hour?

________________________________________________________________

This means that, as the earth rotates, it takes one hour for it to move ______

degs on its axis.

Time Zones explained...

Your friend who lives in Greenwich, England, plans to call at

8:15 pm your time to wish you happy birthday on Saturday.

Imagine that you live in New York City. What time and day will

it be in Greenwich when your friend telephones?

Solving the problem…

___________________________________________________

___________________________________________________

___________________________________________________

___________________________________________________

___________________________________________________

___________________________________________________

Practice problem