Establishing a global algorithm for water quality mapping from multi-dates images  H. S. Lim, M. Z. MatJafri, K. Abdullah and M. N. A. Bakar School of Physics Universiti Sains Malaysia, 11800 Penang Introduction Water quality assessment of ocean and inland waters using satellite data has been carried out since the first remote sensing satellite Landsat-MSS has been operational (Thiemann and Kaufmann, 2000). Many researchers used satellite images in their investigations [Allee, et al., (1999), Forster, et al., (1993) and Ritchie, et al., (1990)]. However, in this study we used airborne remote sensing. A digital camera was used as a sensor to capture the images at altitude of 8000 feet. The main objective of the present study is to update our proposed algorithm for mapping total suspended solids in marine environments using digital camera images from previous study (MatJafri, et al., 2002). We also attempted to develop a simple correction technique for the airborne images acquired from different dates, locations, and different flying altitudes. Data from seven image scenes were combined in the present analysis. This study also proposed a cheaper and economical alternative to overcome the problem of obtaining cloud-free scenes in the Equatorial region. Study Area In this study, a Kodak DC290 digital camera was used as a sensor and a Cessna 172Q aircraft was used as a platform to capture images of the study areas. The study areas were the Prai, Muda, and Merbok river estuaries, located within latitudes 5o 22’ N to 5o 24’N and longitudes 100o 21’E to 100o 23’E; 5o 34’ N to 5o 36’N and longitudes 100o 19’E to 100o 21’E; and 5o 39’ N to 5o 41’N and longitudes 100o 20’E to 100o 24’E, respectively. The images were captured from the altitude of 3,000 ft on 28 October 2001 and 8,000ft on 9 March 2002 for Prai River estuary, 8,000ft on 20 January 2002 and 9 March 2002 for Muda River estuary, and also 8,000 ft on 5 May 2002, 25 October 2002 and 22 March 2003 for Merbok River estuary. The study areas are shown in Figure 1. Water samples were collected from a small boat within the areas covered by the scenes simultaneously with the airborne image acquisition and later analyzed in the laboratory.  (Source: Microsoft Corp., 2001.) Figure 1. Study area
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