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Figures (06),(07) and (08) illustrate the phenological 
sequences of the main crops in the zones being examined. These 
calendars were used in both the choice of Landsat scenes and 
the identification of the content of these scenes. Dates of 
purchase of Landsat scenes are given in figures (06),(07) and 
(08); these also represent all the scenes available in Spring 
and Summer up to 1977 when the research got under way; Autumn 
and Winter scenes were not chosen as they held little signifi 
cance; there was a disappointing number of summer scenes because 
of lack of purchases and cloud-cover. 
al) ,a2) ,a3) and a4) groups were established on the basis 
of available data through a multi spectral and multitemporal 
analysisof the four channels. The groups which do not show, or 
show only slight variation in signature c) and d) (urban 
settlements and unproductive surfaces) were identified solely 
by multispectral analysis and checked subsequently. 
A different procedure was used in the identification of 
a5) and b) as an analysis of Landsat scenes alone was not 
absolutely reliable. Tree crops in the area under examination 
(orchards,vineyards) do not cover the soil completely and give 
intermediate signatures somewhere between the underlying land 
and the vegetation signature. The signatures vary then from 
case to case (not only where the land, but also where the pixel 
layout is concerned). 
The same can be said for woods: thick woods can be identified 
from Landsat data whereas sparse woods can be mistaken for 
underlying land . The two groups were checked against conventio 
nal black and white aerial photographs to ensure the maximum 
degree of accuracy.