21 
can be reduced to two dimensions, due to the fact mentioned above. In 
the cluster diagram (see Fig.) the densities of the channel MSS 4 and 
MSS 7 are used for co-ordinates. Numerous different objects are measured. 
The diagram shows that only the cluster for conifer forest is separated 
from other clusters. The other vegetation shapes a continous cluster 
with some centers for deciduous forest, grassland and agricultural vege 
tation. 
A verification is made by mapping selected colour tones, corresponding 
to the clusters in the diagram. 
Mapping all red colour tones in the picture, we get a review of the 
over-all vegetation cover. The ERTS image was taken in October 72, 
where mostly all fields are harvested, until potatoes, rapes and 
Indian corn. 
Conifer forest is easy to detect and map by the dark violet colour tone. 
The discrimination of conifer forest is 100 % correct, because the 
cluster of conifer forest is separated from other objects, only the 
colours of water are near the cluster. 
The colour composition shows various red and violet colour tones, 
which belong to different kinds of vegetation, like measured in the 
cluster diagram. 
For a classification and mapping the different red colours or hues 
are transformed into a gray scale, each gray level represents another 
hue. From this b/w picture the gray levels are quantized by arbitrary 
steps into several ranges. Each range is displayed in a different colour. 
The result is a colour coded map of vegetation, areas without vegetation 
appear clear white. This unsupervised classification is then brought in 
agreement to types of classification using the cluster diagram and 
ground truth measurements. The overlapping of different types of vegetation 
in the colour space, shown in the cluster diagram, does not give an exact 
determination. 
CONCLUSION 
The investigations are continued. Additional texture analysis is neces 
sary for agricultural research. A comparison of ERTS images and aerial 
photographs from underflights is going on. The work is supported from 
Bavarian ministries and is useful for a general land use planning and 
management and environmental survey.