Quiz2_questions

# Quiz2_questions - QUESTIONS FOR QUIZ 2: GEOG 360 SPRING...

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QUESTIONS FOR QUIZ 2: GEOG 360 SPRING 2008 From the Text: 1. How did Eratosthenes calculate the circumference of the earth ? o Employed simple geometrical calculations o He noticed on the day of the summer solstice that the noon sun shone directly down a well at Syene. However, the sun was not directly overhead at Alexandria but rather cast a shadow that was 7degree 12’ off the vertical. o He knew that the deviation of the sun’s rays from the vertical would subtend an angle of 7degrees 12’ at the center of the earth. o This angle is 1/50 the whole circumference (360). o The only other measurement needed to complete the calculations was the distance between Alexandria and Syene; this was estimated at 804.65 km o Multiplying this figure by 50, he calculated the total circumference to be 40,233 km. 2. What is a Geoid ? o Earth shaped 3. What ellipsoid is used by the North American Datum of 1983 (NAD83) ? o Uses the Geodetic Reference System (GRS80) o Earth- centered (center of mass), and does not have a single origin (a place where the ellipsoid theoretically touches the geoid) 4. How many degrees are in the sexagesimal scale ? o It’s the division of a circle into 360 degrees, each degree in 60 minutes, and each minute into 60 seconds. 5. What is a ‘Great Circle’ ? o The course of the shortest distance between points on the earth 6. What is a ‘Loxodrome’ ? o A line on the earth that intersects every meridian at the same angle o Because of the meridional convergence, a loxodrome theoretically never reaches the pole o also called a rhumb line 7. What is the equation for finding map scale ? o Map scale= map distance/earth distance 8. What are the three types of distortion created during the projection process ? o Tearing, shearing, compression 9. What is Tissot’s Indicatrix ? o Mathematical construct that yields quantitative indices of distortion at points on map projection 10. What is a ‘standard line’ on a projection ? o

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## This note was uploaded on 04/07/2008 for the course GEOG 360 taught by Professor Willis during the Spring '08 term at Binghamton.

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Quiz2_questions - QUESTIONS FOR QUIZ 2: GEOG 360 SPRING...

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