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This then presented a sample area which can be analyzed for pixel values –note
the high degree of shade in the south east and exposed rock in the north west of
the area. The next step in the process involved analyzing the histogram data for
the target sample. This was completed in Geomatica, with the pixel count reduced
to remove the values counted outside the image values. In other words the
irregular image was stored as a GeoTiff image which placed the area onto a blank
background, resulting in a high pixel count for values above the expected range
(in the order of thousands), which were discounted by reducing the pixel count.
Figure 33: Red colour band for rough pasture test 1
The above histogram shows the values for the red colour band, with a clear peak
for pasture values (see sampling section). The lesser spike of pixels of lower
values is consistent with the type of shade expected in this type of area, while the
slightly higher values returned by the exposed rock distorted the standard
deviation slightly. The areas content, however, can be clearly seen in the spike for
pasture, something which is clearer to see in the histogram for the green colour
band:
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