ESPM 172

Laboratory Exercise 3
Point Transfer, Photo Preparation and Individual Type Mapping



1. To learn how to accurately transfer points from one photograph to another.
2. To learn how to prepare photographs for mapping purposes.
3. To introduce and practice the concepts of type mapping from aerial photographs.

Hand in:

Acetate sheet containing initial type map; set of three aerial photographs with principal points and conjugate principal point located on them. Due at the beginning of the next lab period.


1. Point Transfer

a. locate the principal point of each photo.
b. locate the conjugate principal points on the three aerial photographs.
c. transfer an additional three points.

2. Photo Preparation

a. secure the sheet of acetate to the center aerial photograph (photo#3),
b. locate the fiducial marks on the acetate and indicate their orientation,
c. locate the principal point and conjugate principal points on the acetate,
d. draw the flight line (with a straight edge!), and
e. locate and draw the boundaries of the effective area:

(1) Western and Eastern boundaries are perpendicular to the flight line and they pass through the conjugate principal points.
(2) Northern and Southern boundaries are parallel to, and 1.5 in. in from the edge of the photograph.

3. Individual Type Mapping. Each person will develop his or her own classification system in this lab exercise.

On a separate sheet of paper
a. Define the map objectives, and explain the factors that you are interested in. For this exercise limit the choices so that there are no more than 12 distinct classes.
b. Define the classification system, and develop a key (codes and definitions). The key should appear on the acetate with the definition symbols.
c. Prepare a neat type map of the effective area.