1. Finding Locations on Earth

2. Reference Points
Points on earth’s surface used to establish direction.
North & South geographic poles
Plus the imaginary line dividing the earth into N & S hemispheres = equator

3. Latitude (Parallels)
Imaginary lines used to establish north-south location.
These circles run E & W around the world parallel to the equator.
Angular distance N or S of the equator.

4. Latitude (Parallels)
Angular distance measured in degrees North or South of equator.
All locations N & S of the equator have latitude between 0o and 90o.
Latitude at equator = 0o
1 degree of latitude = 111km

5. Latitude 1 degree is broken into 60 parts = minutes
1 min of latitude = km
Each min is broken into 60 parts = seconds
1 sec of latitude = km

6. Washington D.C. Latitude = 39o N More precise = 38o53’ N
Shows minutes of lat.
or 38o53’51” N
Using degrees, min, & sec of latitude.

7. Longitude (Meridians)
Imaginary lines used to establish east-west location.
Each meridian is a semicircle running from pole to pole.
meridian passing through Greenwich, England = prime meridian.

8. Longitude (Meridians)
Angular distance measured in degrees east or west of prime meridian
All locations E & W of prime meridian have longitude between 0o and 180o.
At equator 1 degree = 111 km but this varies.

9. Washington D.C. Longitude = 77o W. More precise = 77o0’ W
Shows degrees + minutes
or 77o0’33” W.
Degrees + min. + seconds

10. Latitude & Longitude Latitude and Longitude of Washington, D.C.
38o53’51” N, 77oO’33” W

11. Our approximate location…
78o W

12. Great Circles Another imaginary line used in navigation.
A great circle is any line that circles the earth dividing it into two equal halves.

13. Finding Direction Use a magnetic compass to indicate direction.
Compass points to geomagnetic north pole which is at a 11 degree angle from geographic north pole.
True north = geographic N

14. Time Zones Earth rotates in 24 hours There are 24 times zones
Locations east of us are AHEAD in time
Locations west of us are BEHIND in time
Each time zone = 15o of Longitude

15. US Time Zones Eastern Standard Time Central Standard Time
Our time zone
Central Standard Time
1 hour behind us
Mountain Standard Time
2 hours behind us
Pacific Standard Time
3 hours behind us