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Malaysian Tiungsat-1 Imagery for Water Quality Mapping
The best Tiungsat-1 image available for the study area did not have the coincident data of total suspended solid. To overcome this problem we correlated the Tiungsat-1 image with the Landsat TM images that have the corresponding sea-truth data. All the three bands of the images ware correlated and examined. The analysis revealed that the Landsat TM image of 20 January 2000 produced the highest correlation with the Tiungsat-1 image. Then the data collected on 20 January 2000 were used in the present study. Figure 2–4 show the DNs correlation between red, green, and infrared bands of Tiungsat-1 image with the corresponding TM bands.
 Figure 2. Graph of DNs relationship between Landsat TM image and Tiungsat-1 image for red band  Figure 3. Graph of DNs relationship between Landsat TM image and Tiungsat-1 image for green band  Figure 4. Graph of DNs relationship between Landsat TM image and Tiungsat-1 image for infrared band The digital numbers (DN) for each band corresponding to the sea-truth locations were determined. The station locations were computed using the second order polynomial transformation equations determined from ground control points (GCP). Digital numbers were determined for each band using different window sizes, such as, 1 by 1, 3 by 3, 5 by 5, 7 by 7, 9 by 9 and 11 by 11. The DNs values extracted using the window size of 7 by 7 were used due to the higher correlation coefficient (R) with the sea-truth data. The data shows positive correlations between DN and TSS. Such characteristics were also observed by other investigators using remote sensing data in the visible channel for suspended sediment studies (Collins and Pattiaratshi, 1984, Schiebe et al., 1992, Choubey, 1992). |