THE USE OF THE THEMATIC MAPPER FOR THE ANALYSIS OF EUTROPHIC LAKES - A CASE-STUDY IN THE NETHERLANDS

Landsat TM images were analysed to assess the scope and limitations of their use for inland water quality detection. The spectral information in the six visible to middle infrared bands is discussed. The relatively wide spectral bands, 1 to 4, of the TM, in the optical wavelength domain contain a mixture of spectrally opposing features of absorption and scattering. Qualitative and quantitative analysis is carried out. The limiting factors in the quantitative determination of water quality parameters are in first instance the radiometric resolution and in second instance the spectral resolution. Combinations of spectral bands of the TM are discouraged for analysis purposes as long as a physical explanation of the result is lacking. Under ideal circumstances the TM can be used to assess seston dry weight, sum of chlorophyll a and phaeopigments, Secchi depth transparency with limited accuracy.