Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Height h0 of an observed object is correctly reproduced at the picture when it is observed at the right angle (upper view). In the case when there is a deviation from the right angle by the angle α, the reproduced height h of the object is smaller than h0 (lower view).
