SUM-SINES EQUATION FOR ESTIMATING THE PERCENT OF SHADOW LENGTH OF TARGETS IN THE SATELLITE IMAGES

Abstract

With the development of high resolution sensors in remote sensing satellites, the shadow phenomena has appeared clearly in satellite image. The shadow is a separated feature in the satellite image, some time it may be considered as a problem due to the loss of ray information at the shaded region, other may be considered as a criteria to the height of the body which has a shadow. The length of shadow depends on the height of the body, location on the earth surface, and the sun location in sky at the imaging time. The sun location is varying every hour during the day and every day during year. These varying is calculated by complex astronomic equations. In this article, we simplified these calculations to just on equation depend on one parameter, and examine this equation by field measurements. The suggested equation is sum-sine equation with an enough accuracy to be used in civil, ecological, gardens designing near the high buildings, or architectural purposes. The equation can be used to estimate the building height from the shadow length in the satellite image, as will as it may used to estimate shadow length from the known body height on the earth.