Establishment of landsat MSS spectral classes of fairly homogeneous tropical peat swamp forests by transect analysis on the Orser batch-oriented image analysis system
Along the transects, a succession of blocks of 10X10 pixels were statistically analysed (STATS). Mean spectral reflectance values for all bands were then plotted along the transects. Vegetation index values, (VI-(5-7)/(5+7)). Were also plotted. Subsequently, covariance matrices from the statistical analysis were used in canonical analysis (CANAL) to enhance block separability.
Coupled with information from cluster analysis (CLUS) and various collateral data, the information obtained from various spectral or signature classes found along the transects. The spectral classes for all the transects within each study area were then compared, and the similar ones were discarded. As such, a set of spectral classes for each study area was identified.
The established spectral classes and their specified limits were coded in various characters and then used to classify (CLASS) the study areas. Minor modification of the mean spectral reflectance values for various classes and their limits, however, might be required. The study areas were then geometrically corrected, rotated and rubber-sheet stretched (SUBGM and DISPGM). This was followed by cleaning of stray symbols and production of compressed maps (DISPLAY). Finally, the compressed maps were used for visual display and colour hard copy print out after scaling.
Spectral variations within the peat swamp forests
The transect analysis indicated that there were significant variations in the spectral reflectances of the Landsat MSS data over these peat swamp forests. Examples of the mean brightness and vegetation index values of all the blocks plotted along selected transects in Pahang and Sarawak, as well as the block separability, are presented in
Figure 1 and 2, respectively. Generally, the spectral responses, especially those in the near infrared regions, changed toward the center of the peat areas. The vegetation indicates also indicated the decreasing biomass in the same direction.
Figure 1. Landsat MSS brightness values and vegetation values and
vegetation index of 10 X 10 pixels blocks, and their separability
based on canonical analysis, along a selected transect over
Pahang
peat swamp forest.
Figure 2. Landsat MSS brightness values and vegetation values and
vegetation index of 10 X 10 pixels blocks, and their separability
based on canonical analysis, along a selected transect over
Sarawak
peat swamp forest.
