Coordinate System YouTube Lecture Handouts
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Coordinate System & Time Calculations - Fundamentals of Geography
Directions, Coordinate System & Time Zones
Agenda
- Understanding directions
- Coordinate system and degree
- Latitude and Longitude
- Time and Date Delineation
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Direction on a Map
- Why draw maps with north at the top?
- Standard convention.
- Compasses are made to measure to the magnetic north pole of the Earth.
Finding the North?
- Left hand to west
- Right hand to east
- Face towards north
North on the Map
- Magnetic north is measured by a compass.
- Grid north follows the grid lines of the coordinate system the map is made on.
- True north corresponds to the Earth՚s axis, the North Pole.
Magnetic Declination
- Difference or angle between magnetic north and true north
- Topographic map depicts difference
Measure Direction on a Map
- Use protractor or compass to measure degrees or angle from north line
- Both measure use circle of 360 degrees
Cartesian Coordinate System
Map Grid
- Imaginary lines crossing the globe
- Meridian lines or longitude are drawn north-south
- Parallel lines or latitudes are drawn east-west
- Coordinate point is intersection of latitude and longitude
Coordinate Systems
Two common coordinate systems are:
- Geographic coordinate system
- Universal Transverse Mercator (UTM)
Geographic Coordinate System
- Latitude lines run east-west and are parallel.
- Longitude lines run north-south & are called meridians.
- Lines are numbered in degrees, minutes and seconds similar to a clock.
- Degrees is used as measurement tool because angles are always measured in degrees.
Latitude & Longitude
Latitude-Longitude
Understanding Terms
- Each degree is divided into 60 minutes
- Each minute is divided into 60 seconds
- Holds true for both latitude and longitude
- Latitude: Distance from equator along Y axis
- Longitude: Distance from prime meridian along X axis – total 360 meridians (180 east and 180 west of prime meridian)
Universal Transverse Mercator (UTM)
- UTM lines are straight on global map
- UTM is a type of projection, calculated to make a flat map of the round Earth.
- UTM zones are numbered east to west and lettered north to south.
- Each zone is equivalent to 6o and is measured in meters.
UTM
Problem 1: Find Out Location on Map?
Problem 2: Basics of Time
- Problem: If it is noon where you are, would it be before or after noon for someone that is east of you?
- After noon
- Recall, the sun rises in the east and sets in the west
- As you look down from the north pole, the earth would rotate counterclockwise
- If the sun is just beginning to rise in California, then the sun would be near noon in New York, so …
- As you travel east, time becomes later
Time Zone
- Earth is divided into 24 time zones!
- because the Earth Rotates
- 1 Time zone for every 150 of Longitude
- The Earth Spins 3600 in 24 hours
- hours
- Or longitude is 4 minutes
- We measure from Prime Meridian in Greenwich England
- Every to the East =+ 1 Hour
- Every to the West =- 1 Hour
Greenwich, England is Initiation Point for Time Zones
- World rotates west to east (counterclockwise) , so time zones to the east are ahead of the those time zones to the west
Problem 3 – Time Zone
How many hours difference is there between Tokyo?
- So the difference is
- Since one hour is 150 longitude
- So it is hours.
- Now Tokyo is east of Rome, so it is 8 hours later in Tokyo.
International Date Line
- Located in mid-Pacific Ocean near 180° longitude.
- Crossing IDL from east to west, it՚s the next day (+ 1 day)
- Crossing IDL from west to east, it՚s the previous day (-1 day)
Problem 4 - IDL
- It is 9 AM Saturday in California what time is it in Australia ?
- So, it is per hour = 7 hours
- So total time difference is 7 hours, since travelling east to west, time becomes earlier it is 7 hours before, i.e.. , 2 AM
- Also you are crossing IDT east to west, so it becomes next day, therefore time in Australia is 2 AM Sunday
Daylight Savings Time
- Used mainly in USA to add an “extra” hour of daylight in the afternoon during spring/summer
- “Spring forward and Fall back”
Problem 5 - Sunrise/Sunset Time Corrections
- If sunset in Winnipeg what is the time for sunset in Manitoba
- Difference is
- longitude is 4 minutes
- longitude is minutes
- So, it is 32 minutes late, i.e.. , 5: 25 PM + 32 minutes = 5: 57 PM
Time Zones - World Map
Jet Lag
- Medical phenomena that occurs due to crossing the various time zones
- Characterized by extreme fatigue, disorientation and loss of appetite.
- Sleep is seen as one of the best cures for jet lag, as is exposure to sunlight.
- It is considered that it takes 1 day per time zone to recover from jet lag.
✍ Manishika