Each digital photo series site generally displays at least one wide-angle photograph and a stereo photograph pair.  

The sign in these photographs is a 1-foot square, and the pole is painted in contrasting colors at 1-foot intervals to provide scale. 

The pole is 30 feet from the camera. 

Summary data relate to the field of view of the stereo photograph pair but are based on measurements taken in the sample area only. 

No sampling occurs in the foreground between the camera and the sign.

Electronic images are available in the digital photo series.