Latitude, Longitude, and Time Zones

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 (4,7) Each point has two values: An X value that runs along the horizontal X axis and... A Y value that runs along the vertical Y axis X axis Each point is expressed as an X value and a Y value with the X value written first. For example... and... 7,5)

Typical Graph (-X,+Y) Y (+X,+Y) X 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. (-X,-Y) (+X,-Y) Now let s apply the same principles to latitude and longitude.

90 N What is latitude? Latitude is a horizontal line along the x-axis of the globe called a parallel It is expressed in degrees. The north pole is 90 N The south pole is 90 S The equator is 0 latitude. 90 S 0 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 a vertical line running north and south along the y-axis 180 0 180 Just like latitude, longitude is measured in degrees. Lines of longitude are called meridians The prime meridian is 0 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.

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

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?

43 N Let s look at Ithaca, NY, the home of Cornell University. 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.

Degrees and Minutes Each DEGREE can be subdivided into 60 MINUTES This is true for BOTH longitude and latitude. 43 N 77 W 60 minutes 76 W 60 minutes 42 N

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 PARALLEL 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