USE OF ASTER AND LANDSAT DATA IN MAPPING ...

Egypt. J. Remote Sensing & Space Sci., V. 7, pp. 3-14 (2004)

USE OF ASTER AND LANDSAT DATA IN MAPPING LAND USE/ LAND COVER AND SOIL CONDITIONS IN THE EASTERN NILE DELTA, EGYPT H. El-Gamily1; R. R. Ali2 and A. Gad1 1- National Authority for Remote Sensing and Space Sciences (NARSS), Cairo, Egypt 2- National Research Centre (NRC), Cairo, Egypt Abstract. The study area is located at northeastern part of the Nile Delta of Egypt, between latitudes 31°12´40´´ to 30°42´49´´ N and longitudes 32°06´53´´ to 31°20´31´´E. and it presents a promising area for both agricultural expansion and urban development. It covers an area of about 1031 Km2. Major activities in the area are running in relation with the installation of the eastern irrigation commands of El-Salam Canal. Projects of fisheries and reclamation of saline soils dominate in the area. This study aims to test the recent satellite data obtained from new generation of space sensors (i.e. ASTER) in mapping land use/land cover. It is also desired to conclude the additional advantages of ASTER data over the conventional LANDSAT images. In this study the ASTER image of May 2000 released by NASA Web site (NASA GSFC, MITI, ERSDAC, JAROS, and U.S./Japan ASTER Science Team) and LANDSAT ETM+ image, dated 2001 were used to map different classes of land use / land cover (LU/LC). The images were geometrically corrected, enhanced and classified on the basis of their spectral characteristics. The obtained enhanced and classified images were interpreted and validated by collection of soil and landscape data.. It was possible to identify 10 land use/ land cover classes from ASTER data and 8 classes from LANDSAT ETM+. The classes of "dried fish farms for land reclamation" and “fish farms and water bodies” nearly represent similar percentages in both LU/LC maps. Fallow fields, halophytic plantation and gypsiferous soils were accurately delineated from ASTER data, but were mixed with other classes in the LANDSAT ETM+ data. ASTER data permitted to separate 10.7% of study area as irrigated fields and shallow water bodies It was possible to delineate a zone of sandy deposits at the south of study area, however many of pivot irrigation systems were erected referring to reclamation of sandy soils. Spectral interference between saline soils and sandy deposits could be overcome by combining both types of data, thus multi sensor approach is recommended to handle spectral conflicts. Land suitability classification for 11 crops proved that the major limitations in the salt affected soil are salinity, alkalinity and soil depth. The suitability limiting factors in newly reclaimed sandy soils include soil texture and depth. Predicted yield for wheat, corn and cotton in the northern part of study area are highly compared with the southern district. It could be concluded that ASTER data is a powerful tool for operational monitoring of land use / land cover, comparing with LANDSAT one.