COMBINATION OF DIGITAL ELEVATION MODELS WITH SPOT-1 HRV MULTISPECTRAL IMAGERY FOR REFLECTANCE FACTOR MAPPING

Digital numbers in SPOT-1 HRV multispectral imagery were transformed to reflectance factor values. This approach is based on a simplified-scene radiance equation that is developed in this paper. The values of some parameters needed in the equation such as path radiance, total normal optical thickness, and diffuse spectral irradiance were estimated by using multiple linear regression in a small test site of homogeneous ground cover, located within the study area. The calculated values of reflectance factors were presented by dimensionless digital numbers ranging from 0 to 255, which corresponds respectively to the values of reflectance factors from 0 to 1. The feasibility of this approach has been tested against the SPOT-1 HRV multispectral imagery above a canopy of Picaussel Forest of the Quillan region in the eastern pyrenean mountain in France. © 1990.