PHOTO SCALE AND COVERAGE

THIS PROJECT TESTS YOUR COMPUTATIONAL KNOWLEDGE OF PHOTO SCALE AND COVERAGE BY ASKING QUESTIONS THAT REQUIRE MATHEMATICAL SOLUTIONS.-USE THE AIR PHOTOS HANDED OUT IN CLASS TO ANSWER THESE.

DUE --Tuesday - October 20- 10 PT LAB. (DO YOUR OWN WORK!)

Part 1. - Computing Photo Scale and Coverage Using a Map of Known Scale

A. What is the scale of the aerial photo in Figure 2.2, based on the 1:24,000 map in figure 2.23?

Procedure:

1. Locate two points on the map (figure 2.23) that can be readily identified on the photo. Selected points should be a widely separated as possible to minimize measurement error. Identify these points on BOTH the photo and the map with visible dots.

2. Using an engineers scale or ruler, measure the distance between the two points on the map. With the aid of the map scale, convert this measurement to actual "ground distance" between the points. Enter this distance for ground distance (GD) in the equation below.

3. Now measure the distance between the same two points on the photo (figure 2.22) and enter this value as the photo distance (PD) in the equation.

RF = PD/GD

Solve the equation to determine the representative fraction (RF) scale.






Part II

1. Based on the track in figure 2.24, what is the scale of the photo?




2. Compute the scale of the imagery in figure 2.25, based on the scale of a known objects in the photo. (Determine the scale for two or three features you can identify and then average all scales together for your answer.)