Recognition of granitic rocks using Landsat ETM+ images
processing Eastern Desert, Egypt.
Esam, M. Abdel Motaal ⃰, Ahmed, M. A. Orabi ⃰ ⃰, and Mostafa, K. Abdel Ghany ⃰ ⃰.
⃰ Al Azhar Univ., Faculty of science, Geology department, Cairo.
⃰ ⃰ Al Azhar Univ., Faculty of science, Geology department, Assiut branch.
ABSTRACT
The present study aims to find out how far the remotely sensed data can be used
to discriminate between different types of granitic rocks in the Eastern Desert and
how can use the capabilities of the geographic information systems (GIS) in order to
map these granites.
ETM+ single bands, false color composite, principal components, bands ratio,
supervised and unsupervised classification images were used in the present study.
These different processing corrections as well as processing methods of ETM+
images have been applied in order to build up a geosensing map and proven to be
useful for classification of the granitic rocks and creating map to this classification in
the study area.
Digital processing of Landsat -7 ETM+ for the investigated area generated
several products including false color composites images (7, 4, 2) and (7, 3, 5), band
ratioing images (3/1x7, 2/4x3, 5/3x7), (7/5, 2/1, 3/5) and principal components (PC3,
PC1, PC4) are useful used to discriminate between the older and younger granites.
The older granites have been classified into two groups; first group (Granodiorite) and
second group (Tonalite granites). The younger granites are also differentiated into
three group; (Syeno -Monzogranites), (Alkali granites) and (Granodiorite).
The structural lineations of each granitic body have been studied and the result
show that the preferred orientations of lineaments traced of these rocks from each the
granitic bodies lead to grouping of these rocks and support the use of spectral
characteristics in classification and grouping of granitic rocks.
The capabilities of geographic information systems have been used to integrate
all these studies together in order to build up a database for the discussed phenomena
and to handle easily the data.