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Generally then, it was concluded that false colour photography could be
successfully used, especially where vegetation types were related to
soils, but that at the same time the season in which photograph was
obtained might be critical.
A second project has used remote sensing for conservation evaluation by
obtaining ecological data from aerial photography. Two study areas were
considered, the Gairloch Conservation Unit which is situated in the up-
lands of Wester Ross, Scotland, and a lowland coastal area in the
Merseyside Metropolitan County.
An examination of the available aerial photography showed that black
and white vertical photos of 1:10000 scale (taken in 1971 and 1972) most
comprehensively covered the study areas. Some colour photography existed
for the Gairlock area while parts of the Merseyside area were covered by
false colour photography but neither were extensive enough to fulfill the
aims of the project.
Using the black and white photography, ecological habitats were mapped
for each area and were found to correspond mainly to vegetation units in
Gairloch and to land use categories in Merseyside. One important point
which emmerged at this stage was that on a priori classification based
on fieldwork was not readily applicable to air photo interpretation.
It would seem that a "photo-ecological" classification, i.e based on
photo evidence, would therefore be more appropriate to studies of this
kind.
Timing of the photography was also seen to be significant in achieving a
successful survey. In the case of Gairloch, photography was obtained
during September 1971 which seasonally was probably ideal (this compares
with the late Summer/early Autumn photography of the Ingleborough soils
project). However photography was taken apparently in the early morning
resulting in deep shadow around steep rocky outcrops. This prevented
any confident identification of habitat types. A similar problem occurred
in Merseyside where photography was obtained during May to August 1972,
Seasonally this presented little problem particularly since habitats were
more closely related to land use. However it was difficult to map
boundaries of salt marsh since low tides, when the plant communities
were most visible, were not normally recorded on the photographs.
In spite of these difficulties black and white photography appeared
quite adequate for mapping habitats although an examination of the limited
colour and false colour photography indicated that they might have some
advantage in certain areas. For example, true colour would probably be
more useful in differentiating between vegetation and bare rock in mount-
ain top communities (Gairloch), while false colour could aid the identi-
fication of freshwater marsh (Merseyside).
The analysis of the habitat data is described elsewhere (Nichol, 1975)
whilst a fuller description of the complete work is presented in another
paper in this volume (Nichol and Collins, 1978), It is sufficient to
state here that the end result of the project was a series of computer
drawn maps showing areas of varying ecological importance. Such maps can
be used for conserving the most important areas by allowing only com-
patible land uses to be developed, with necessary development taking
place in those areas of least significance.