  The shadow is a separated feature in the satellite images specially high
resolution images. It may be looked as a problem when it causes a loss in the
ground ray response to the shaded area, and may be, from other view, considered
as an indication to the height of the bodies or buildings, when it hidden due
to top view of the satellite image usually. The location of the object on the
earth affects its shadow length, direction and darkness. The ostensible sun
path in the sky also affects the shadow length and direction, it is depending
on the change of the rotation axis of planet about its center during the year.
And it is clear that the shadow is changing with the sun transmission in the
day times. The sun location needs complex equations, because there are several
angles describing its location with taking into consideration the location of
the shaded body on the earth spatially the latitude, and the shadow direction
and length depend on the sun location so it need more equations. Some
engineering purposes, and some engineers and designer can not process these
complex astronomy equations every time they need to calculate the shadow effect
on the urban region or garden for examples, or other architectural purposes, it
is unpractical process to estimate the shadow direction and length for civil
from these equation. So, we derived in this study a high accurate empirical
Gaussian equation to find shadow length percent in the limits of the study area
depends on single parameter which is the number of day during the year, and
calculating the percent of shadow, so we can calculate the shadow length
percent accurately in any day number by the suggested equation after knowing
the real building height.
