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Establishing a global algorithm for water quality mapping from multi-dates images
Verification analysis
For the verification analysis, sea truth data were divided into two groups, half of the
numbers of water samples were radom selected for algorithm calibration and the another
half of the numbers of water samples were radom selected for verification analysis. The
calibrated algorithm was produced high accuracy with R value of 0.9685 and RSM value
of 13.19 mg/l in the verification analysis. Figure 6 shows the relationship of the measured
TSS versus estimated TSS concentration for algorithm calibration analysis. Figure 7
shows the relationship of the measured TSS versus estimated TSS concentration for
verification analysis.
Figure 6. Measured TSS versus estimated TSS concentration for algorithm calibration
analysis
Figure 7. Measured TSS versus estimated TSS concentration for verification analysis
Conclusion
This study gives a cheaper way to overcome the problem of difficulty of obtaining cloudfree
scenes at the Equatorial region. Traditional water quality monitoring method based
on water sample collection is time consuming and requires a high operating cost. It is
good for determined the water pollution for real time. The proposed algorithm is
considered superior to other tested algorithms based on the values of the correlation
coefficient, R=0.97 and root-mean-square error, RMS=15mg/l. This indicates that the
TSS maps can be generated using digital camera imagery with the proposed algorithm.
Acknowledgement
This project was carried out using the Malaysian Government IRPA grant no. 08-02-05-
6011 and USM short term grant FPP2001/130. We would like to thank the technical staff
and research officers who participated in this project. Thanks are extended to USM for
support and encouragement.
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