616
C D
p hotographs: Selected photomorohic features presented on colour IR air photographs. Original scale 1*26,000
A. Linear features representing oaleocoastal environment of proglacial lake* beaches, sand bars, spits,
troughs
B. Convoluted features representing ice-collapse, glacio-lacustrine sediments.
C. Elongated to irregularly shaped oaleo-dunes
D. Contemporary floodplain of the Thames River.
4.2 Digital Analysis
Airborne multispectral scanner data (MEIS-II) have
been subjected to image analysis procedures using a
Dipix, (Aries-II) System. Data processing and
enhancement operations included optimal band
selection, contrast stretches, spatial filtering
and principal component transformation, prior to
visual interpretation.
5 RESULTS
5.1 Black & white panchromatic air photographs
Panchromatic, B&W air photographs, taken in late
summer provide limited information for surficial
geological mapping due to the masking effect of
vegetation and subdued relief. Only broad delinea
tion of physiographic units likely to reflect
geological units are possible.
5.2 Colour
The colour
conditions
emergence
better exp
The six ma
clearly de
include; (P
a. Linea
landforms
ment of pr
spits, tro
b. Convo
glacio-laci
c. Elong;
d. Contei
e. Moraii
f. Hummoi
5.3 Digita:
a. Selectic
The select:
using a rai
(1985). T1
nm), CHOO
Imagery fr<
enhancement
visual inti
b. Contrast
Histogram-«
the best r«
of colour c
triplet.
c. Spatial
Best result
The enhance
accentuatir
glaciolacus
naleo-dunes
d. Principa
A principal
Waltz, 1979
material ar
optimal thr
e. Band rat
After elimi
bands, the
CH05) were
images. Be
surficial m
features we
CH05 (blue)
Enhanced di
equalisatio
to better i
photomorohi
been oartic
mation deri
The incre
does not al’
nition of s
conditions
humus conte
plowing, ca
after enhan
nhotomorphi