2. Coordinate System Unit 1: Mapping the Earth
This unit is comprised of two main concepts; our coordinate system based on latitude and longitude, and using
topographic maps that indicate landforms and human construction.
Concept 1: Our coordinate system
Big Ideas: see NYS standards for mapping. Key Idea 1: 1.1c and 1.1d and 1.1f.

3. 1. Our planet is a rotating sphere
1. Our planet is a rotating sphere. Drawn to scale, it is perfectly round. The equatorial diameter is greater than the polar diameter.

4. 2. Latitude gives locations in degrees north and south of the equator
2. Latitude gives locations in degrees north and south of the equator. There are 90 degrees from the equator to the North Pole and from the equator to the South Pole.

5. a. Temperatures change with latitude
a.     Temperatures change with latitude. The solar noon angle of the sun’s rays decreases towards the Poles, because earth is a sphere.
NASA climate science investigations

6. b. Polaris is visible only in the Northern Hemisphere
b.     Polaris is visible only in the Northern Hemisphere. The altitude of Polaris equals the observer’s latitude in the Northern Hemisphere.

7. c. Each degree of latitude equals approximately 112 km or 70 miles.
d.     Lines of latitude run parallel to the equator and are called ‘parallels’.

8. e. New York State’s latitude is between 40 and 45 North latitude
e.     New York State’s latitude is between 40 and 45 North latitude. As seen on page 3 of ESRT, the degrees of latitude are each divided into 60’.

9. 3. Longitude gives locations in degrees east and west of the Prime Meridian (PM) to the International Date Line (IDL).
a.     The Prime Meridian is an arbitrary line with a value of 0. The IDL is 180 from it.
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10. b. There are 180 East of the PM and 180 West of the PM
b.     There are 180 East of the PM and 180 West of the PM. The date changes at the IDL.
c.      Lines of longitude are called meridians, and come closer together at the Poles. There is no set distance between lines of longitude.

11. d. Time changes with longitude because the earth is rotating at a rate of 15 /hr.
e. There are 24 time zones of 15 degrees longitude each. Due to earth’s rotation from west to east, locations East of an observer are later and locations West are earlier.

12. http://www. google. com/url

13. f.       New York State longitudes are between 72 W and almost 80 W.

14. 4. Coordinates: Earth’s coordinate system is really a graph or grid.
a.     The coordinates of any location on earth are the latitude and longitude.
b.     The coordinates must include direction. Montgomery, NY is 41 30’N, 74 05’W.

16. 5. Mapping the Earth: Because the earth is round, all flat maps will have distortions of shape and distance.   
The Mercator projection is conformal. All indicatrices are circles; area distortion varies with latitude.
 The Sinusoidal projection preserves area. All indicatrices enclose the same area.; shapes are obliquely distorted.
The Equal-Area Cylindrical projection also preserves area. Shapes are distorted from north to south in middle latitudes and from east to west in extreme latitudes.
In the Robinson projection, neither shape nor area is perfectly right anywhere. Both properties are nearly right in middle latitudes.

17. a.     Page 3 of ESRT is a map of NYS that includes latitude and longitude, and is precise to minutes of each degree.
b.     Page 4 and 5 are Mercator projections of the world.  Mercator is the most accurate for direction.
d.     Improvements in technology allow mapmakers to use satellites, lasers and computers to pinpoint areas on earth accurately and precisely and to identify changes in earth’s surface.