Latitude, Longitude, and
Time Zones
Typical Graph
This is an example of
a typical graph.
It is made up of points
that are connected by
a line.
Y axis
Typical Graph
Each point has two values:
(4,7)
An ‘X’ value that runs along
the horizontal ‘X’ axis
and.......
A ‘Y’ value that runs along
the vertical ‘Y’ axis
Each point is expressed as an X value and a Y
value with the X value written first. For example...
and...........
X axis
7,5)
Typical Graph
Y
(-X,+Y)
(+X,+Y)
X
(-X,-Y)
(+X,-Y)
Graphs may be divided
into quadrants with the
X and Y values being
either positive (+) or
negative (-) depending
on the quadrant in which
they are located.
Now let’s apply the same
principles to latitude and
longitude.
90°N
What is latitude?
Latitude is the distance
from the equator along the
Y axis.
It is expressed in degrees.
The north pole is 90° N
The south pole is 90° S
90°S
0°
And remember that the
equator is 0° latitude.
What is the maximum possible latitude on Earth?
90° is maximum. You could be at 90°N or 90°S but
there is no greater latitude on Earth (or anywhere else)
What is longitude?
Longitude is the distance
from the prime meridian
along the X axis.
Just like latitude, longitude
is measured in degrees.
The prime meridian is 0°
180°
0°
180°
And if you go half way
around the world you will
reach the 180° longitude
line.
Understand that there aren’t two 180° lines. On this FLAT
map it just looks that way. It’s the SAME line.
What is the maximum possible longitude on Earth?
180° is the maximum possible longitude on Earth.
On the map horizontal lines
are lines of latitude and....
vertical lines are lines of
longitude.
The X axis is the equator
Equator
and the Y axis which runs
through Greenwich, England
is the Prime Meridian*
Prime Meridian
* A MERIDIAN is another name for a line of longitude
Any location north of the equator is a NORTH LATITUDE
Where do most people on earth live?
Any location south of the equator is a SOUTH LATITUDE
Any location west of the prime meridian is a WEST LONGITUDE
Any location east of the prime meridian is an EAST LONGITUDE
We can divide the Earth into quadrants: NW where all
latitudes are NORTH and all longitudes are WEST.
Notice that EVERY point in the United States will have a NORTH
latitude and a WEST longitude since we are in the NW quadrant.
60°N, 30°W
75°S, 75°E
15°S, 105°W
Each box on this map is 15°. With that in mind how can we identify specific locations
(red dots)? Remember, write latitude first! (It’s the x coordinate)
What are the coordinates of location......A
What are the coordinates of location......B
What are the coordinates of location......C
But what about location D ? It’s in the middle of a box. What do we do now?
Let’s look at Ithaca, NY, the
home of Cornell University.
43°N
77°W
76°W
The latitude is more
than 42°N
but less than 43°N
and the longitude is
more than 76°W
but less than 77°W
Ithaca
42°N
We need to be more precise. We can do that
by subdividing each degree into 60 smaller
units called minutes.
If there are 60
minutes in each
degree then half
a degree would
be 30 minutes.
Let’s draw in the
30 minute (30’)
line.
See these 2 marks?
They are half way
(30’) between
42°N and 43°N.
Using a ruler,
connect them.
The line you just drew is 42°30’N. Now let’s look at lines of longitude.
See these 2 marks? They are half way (30’) between 76°W and 77°W.
Using a ruler, connect them.
The line you just drew is 76°30’W.
Now let’s see if we can locate Ithaca more precisely.
First comes latitude.
Notice that Ithaca is
just south of the
42°30’N line. If it’s
not quite 30’ then
let’s call it 25’.
Ithaca is located
42°25’N.
Now we’ll do longitude which, for Ithaca is easy since it’s located
right on the 76°30’W line. Ithaca’s longitude is 76°30’W.
Now we’ll put latitude and longitude together to give a
precise location: Ithaca is 42°25’N , 76°30’W.
Here are some things to remember:
> Latitude is written first and must always include N
(north) or S (south) of the equator.
> Longitude is written next and must always include E
(east) or W (west) of the prime meridian.
> Each degree of latitude or longitude can be divided
into 60 minutes.
> A minute, as used here, is a unit of distance on the
earth’s surface. It is not a unit of time.
> Most of the time it will be impossible to be absolutely precise. Your
best estimate might have to be to the nearest 5 or 10 minutes. In other
words, an estimate of 73°25’W is OK but 73°28’W is trying to be more
accurate than is reasonably possible.
Degrees and minutes
Here is how you write degrees and minutes…
40° 32’N (latitude)
10° 43’W (longitude)
TOGETHER> 40°32’N, 10°43’W
Latitude is always given first, followed by longitude.
Typing tip: for the degree symbol, ALT-0176 (Try it!)
LONGITUDE AND LATITUDE
LATITUDE
EQUATOR
LONGITUDE
MERIDIAN
DEGREES
PRIME MERIDIAN
INTERNATIONAL DATE LINE
Why the zigzag line?
TIME ZONES
Time zones are measured by reference to a specific point,
namely the prime meridian which runs through Greenwich,
England. We have commonly referred to time at this point as
Greenwich Mean Time -- GMT
In recent years it has been common to refer to the more
accurate Coordinated
Universal Time (abbreviated
as UTC) which uses an atomic time clock to regulate world
time. UTC is used as a starting point to determine time in
other countries worldwide.
So, for example, if a country is stated as having the time UTC+3,
this means that when it is 1:00 PM in Greenwich, it is 4pm in that
country.
There are 24* primary world time zones
Each time zone spans approximately 15 degrees of longitude
* Because of local and political considerations there are
actually more than 24 officially recognized time zones
WORLD CLOCK
http://www.timeanddate.com/worldclock/
UTC time?
JET LAG?
Many travelers find that they suffer from a condition
known as 'jet lag' when they have crossed time zones.
This is a physiological condition triggered by the body
becoming out of sync with the usual light and dark
patterns to which it is accustomed.
The condition is characterized by numerous symptoms,
such as extreme fatigue, disorientation and loss of
appetite.
Jet lag often takes many days to recover; a rough
medical guideline being one day per time zone. Sleep is
seen as one of the best cures for jet lag, as is exposure
to sunlight.
US TIME ZONES
http://www.time.gov/
FOUR US TIME ZONES
ABBREVIATIONS
•
•
•
•
•
•
•
EST
EDT
CST
MST
PST
AST
HST
So what time is it right now in…
LONDON, England?
PARIS, France?
BOMBAY, India?
CHICAGO?
LOS ANGELOS?
LAS VEGAS?
See page 25 in your NWAt