vislim: R function for computing the limit of visibility of an object given its height
Description
The function allows to plot the angular size of an object (in degrees) against the distance from
the observer, and to compute at which distance from the observer the angular size of the object
hits the limit of human visual acuity (0.01667 degrees).
Usage
vislim(vis.degree = 0.01667, targ.h)
Arguments
vis.degree
Limit of human visual acuity (0.01667 by default).
targ.h
Target size (=height in meters).
Details
The function returns: -a plot displaying the decay in angular size as function of the object's
distance from the observer; a black dot represents the distance at which the angular size hits
the limit of human visual acuity; -the value (in km) of the visibility limit.
# NOT RUN {# calculate the visibility limit of an object of size 6m, and store the result (20.62 km)#in the 'limit' objectlimit <- vislim(targ.h=6)
# }