Representation of the Earth. Geographical coordinates, maps. The scale

1. Representing
the Earth´s
area

2. In order to represent the Earth, we use
simplified representations of the Earth: maps.
Although the Earth is a sphere (well, nearly a sphere, it’s not a perfect
sphere, it’s a geoid), Geographers represent the Earth on a flat surface:
a map. That´s not so easy!
The most common way
to represent the Earth
is the cylindrical projection.
This type of representation
is not perfect.

3. We can also
represent the
Earth with a
globe

5. 1. Physical (or topographic) maps. They
represent natural features: mountains,
rivers, islands, lakes, etc.
The different colours
represent the altitude
Green: low altitude
Yellow: high altitude
Brown and white: very high
altitude

6. 2. Political maps: they represent cities,
countries, villages, etc.
Borders separate countries.
Borders can be physical (a river,
a mountain…) or imaginary

7. 3. Climate and weather
maps: they represent
climates, precipitation or
temperatures on planet
Earth
This is a
map of the
weather
Climate map: we represent
the different climates with
different colours

8. 4. Population
maps
Map key. It helps us
to understand the
map
The darker the color,
the more people live
in an area of the
world.

9. 5. Vegetation maps
Map key

10. 6. Roadmaps

11. Now imagine you have a yatch. You are in
the middle of the Atlantic ocean. But you
have run out of petrol! You need help!
Heeelp!!!Sorry
captain, we
have run out
of petrol!!!

12. It is a modern yatch, and you have a radio!
We need help!
We are here,
in the middle
of the Atlantic
ocean!
Ok. We will help
you. Where
exactly are you?
The Atlantic
ocean is huge!

13. We need to
know your
geographical
coordinates!

14. No problem!
I can do that!
This is a modern
yatch!
Latitude:
30º North
Longitude:
60º West
We´ll be
there
ASAP

15. In order to locate any point on the Earth´s
surface, we use lines called parallels and
meridians. These lines are not real: they are
imaginary lines.

16. The Equator is parallel 0º (zero degrees)
The Equator divides the Earth in
two hemispheres: Northern and
Southern

17. A parallel is an imaginary line running from
East to West, and parallel to the Equator
There are 90 parallels
between the Equator
and each pole.

18. Other important parallels are the Tropic
of Cancer and the Tropic of Capricorn
Tropic of Cancer:
23º 27’ North
Tropic of Capricorn:
23º 27’ South

19. Also, the Artic circle and the Antartic circle
Artic circle:
66º 33’ North
Antartic circle:
66º 33’ South

20. Meridians are imaginary lines running from the
North pole to the South pole.
The Prime Meridian (0º) or
Greenwich meridian crosses
the Observatory at
Greenwich near London.
It also crosses Spain!
The Prime Meridian also divides our
planet in two hemispheres: Western
Hemisphere, and Eastern Hemisphere.
There are 180 main meridians in each
hemisphere

21. Parallels and meridians cross and form a
grid.
I am here!, in
this
GEOGRAPHICAL
COORDINATE

22. What is latitude?
- Latitude is the distance of any point
on the Earth to the Equator. That is:
the distance from a parallel to the
Equator.
- Latitude can be North or South.
- Latitude goes from 0º (the Equator)
to 90º (the North and the South poles).
North
South

23. What is longitude?
Longitude is the distance from any meridian
on the Earth to the Prime Meridian
(=Meridian 0º or Greenwich meridian).
Longitude can be West or East.
Longitude can go from 0º to 180º

25. So where exactly
is Madrid?

26. Latitude:
40°25′ North of
the Equator
Longitude:
3°41′ West of
the Prime
Meridan
These are the geographical
coordinates of the city of Madrid

28. In order to represent on a map the real
world, we need a scale.
A scale is the relationship
between a distance
measured on the map,
and the real distance on
Earth. There are two
types: graphical and
numerical scales. Graphical scale: each
rectangle represents 1,000
meters in reality
Numerical scale

29. Example: the distance between Torrejón de Ardoz and Alcalá de
Henares on a map is 5 cm. The scale is 1:250,000. What is the
distance between these two cities in the real world in kilometers?
Calculations:
5 cm x 250,000 = 1,250,000
cm
1 m = 100 cm
1,250,000 / 100 = 12,500 m
1 km = 1000 m
12,500 / 1000 = 12.5 km
The distance between
Torrejón de Ardoz and Alcalá
de Henares is 12.5 km