Application of optimum index factor technique to landsat-7 data for geological mapping of north east of

Abstract: North east of Hajjah represents the southwestern extension of Nabitah belt which is a part of the Arabian Shield. The geology of the area is very complicated and exposed to the different tectonic movements. Landsat-7 Enhanced Thematic Mapper Plus (ETM+) provides six bands with 30 m resolution, one panchromatic band with 15 m and one thermal band with 60 m resolution. Optimum Index Factor (OIF) is one of the most common statistical methods which were applied in order to designate the most favorable three band combinations. It is based on the total variance within bands and correlation coefficient between bands. In this study OIF technique was applied to all bands of ETM+data. A number of 56 band colour combinations were produced and analyzed using OIF. The highest value of OIF is 45.65 with the first rank which is recorded the band combination 5-6-7. The aim of this study is to use OIF technique to rank all the possible band colour combinations of ETM+data for geological mapping of north east of Hajjah. The different analyses of all OIF values and their ranks showed that OIF technique is helpful for selecting the suitable combination for geological mapping of the study area. Key words: OIF • Yemen • Landsat-7 (ETM+) • geological mapping • combination