Part 4. Dead Reckoning by Pace and Compass

4a. Use the star E as your starting point, and star F as your endpoint. What are the UTM coordinates of these points? (1) (Use your digital quadrangle with the TerraGo Toolbar to find the coordinates.)

Point E (UTM):

Point F (UTM):

4b. Now we will establish the scale of this campus image. Recall that the Δ symbol means “difference”. (3)

i. What is the ΔEasting (Easting2 - Easting1)?

ii. What is the ΔNorthing (Northing2 - Northing1)?

iii. What is the ground distance between the points?   D=SQRT(ΔE2 + ΔN2)

iv. What is the map distance between the points by ruler (in cm)?

v. Fill in the blank:  1 cm (map distance) = ____________ m (ground distance)

vi. What is the Representative Fraction of the map?

(RF = Map Distance/Ground Distance in the same units)

4c. With a partner, construct a dead reckoning plot on the map with four legs that takes you from Point E to Point F. For each leg you will need a magnetic azimuth and a distance.

Fill in your dead reckoning course here. (You will fill in the last column later.)

4d. How many of your paces equal 100 meters?

• Number of paces from Point 1 to Point 2:

• Number of paces from Point 2 to Point 1:

• Average: ______________

• Using the average, what is the length of your pace in meters?

4e. Fill in the last column of your dead reckoning plot by converting each leg’s distances in meters to distance in paces. Do this by dividing the distance of each leg (in meters) by the length of your pace (in meters per pace). For example, if my leg is 100 meters in length, and the length of my pace is 0.64 meters, I need (100 m) / (0.64 m/pace) = 156 paces to walk 100 meters.

4f. How far off were you from the endpoint (in meters) (1)?

4g. What are the sources of error that arose as you walked your dead reckoning course? How might some errors compound? (2) (Answer this question individually, not with your partner.)