The Kingdom of Saudi Arabia has not yet had a full (national) land cover mapping survey. The very limited areas in Saudi
Arabia covered by the 30m resolution DEM level-2 that is compatible with the fine and medium resolution (SPOT and
TM) imagery makes it unreliable as a topographic source. The validity of the lower spatial resolution (100m) DEM level-
1 of full coverage of the Kingdom as a substitute is tested for that purpose. Two approaches to assessment were considered
for this purpose. The first approach, implemented in this paper, involved a comparison between the two DEMs data with
the aid of reference data, whereas in the second, not published yet, the assessment was performed on the radiometrically
corrected image data using the two DEMs data. Visual and statistical analyses have revealed that differences
(discrepancies) between the two DEMs increase with increase of terrain slope, indicating that possibility of DEM level-1
to replace level-2 decreases with increase in terrain slope. The possibility of DEM level-1 to be an adequate alternative to
level-2 would apply in flat to moderate terrain (0° - 5°) only, and is expected to decrease as terrain orientation turns away
from north (highest differences at 271° - 360°). The differences between the two DEMs for west facing slopes (i.e., 181° -
360°) are significantly higher than those for east oriented slopes (i.e., 0° - 180°).
Desert bare soil has been found in literature to exhibit anisotropic reflectance behaviour. Anisotropy is described by
Bidirectional Reflectance Distribution function (BRDF). Literature studies have limited their investigations to the
behaviour of the topographic corrections of Minnaert and C models (simple forms of the empirical type of BRDF) with
terrain variables (slope and orientation). Yet, none of these studies, especially for desert bare soil, has investigated the
behaviour of the coefficient values of Minnaert and C with terrain variables. The investigation in this study has revealed
that the relation between terrain slope (derived from both DEM
level-1 and level-2) of desert bare soil in Saudi Arabia
and K and C values follow closely a 2nd order polynomial trend. K curves have taken convex shapes, whereas C curves
were concave. The Minnaert (K) and C coefficients trends have shown that surface Lambertian behaviour is more
pronounced on slopes facing away from the sun than on sun facing slopes. This author's newly developed terrain slope,
aspect and phase angle dependant's C and Minnaert coefficients produced promising results compared to the global K
and C.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.