data have been found superior to MSS imagery
(Horter and Ahern, 1986).
Latty and Hoffer (1981) studied the utility of TM
spectral bands for a site in South Carolina using
TMS data. They analyzed the statistical
separability of spectral classes using var ious TMS
spectral band combinations. Their results showed
high separability between a number of forest
classes.
Williams and Nelson (1986) report the results of a
Nor th Carolina study where substantial
classification improvements were obtained with TMS
data (relative to MSS data) for seven forest
classes. The overall per formance of TMS
classification was 60 percent as compared to 39
percent for MSS data.
and DeGloria (1985) present the results
actual TM data in forestry
that the best
the MSS data
TM data will
Benson
from the use of
application in Carolina. They stated
TM band combination was better than
and the best results indicated that
provide higher classification.
The paper of Jones et al. (1988) describes the
complementary use of digital terrain information
and SPOT-1 HRV multispectral imagery for the study
and mapping of semi-natural upland vegetation. A
digital terrain model was derived for a study area
in Snowdonia, Wales, and was used to generate
slope and aspect images.
the assessment of
Borry et al. (1990) studied on
the value of monotemporal SPOT-1 Imagery for
forestry applications under Flemish conditions.
Research results revealed that the enhancement
procedure for visual interpretation is of minor
compared to the acquisition data.
visual analysis is lost if
forest information are
impor tance when
The advantage of
detailed levels of
required.
3. MATERIAL AND METHODS
3.1. Study Area
The study area chosen for analysis is located
within the Abant forest and the Alada§ forest area
in the eastern part of Bolu province. The study
site is approximately 943 square kilometers (364
square miles) (Figure 1).
latitude N 40°42’ and
This area is situated on
longitude E 31°28’ with an altitude 738 meters
above the sea level. The area has highly
productive, level to rolling terrain and
intensively vegetated.
The region has semiarid mesothermal climate with
dry summers and cold winters. The coldest month is
January with -4.6 °C mean and the warmest August
with 39.4 °C Annual average relative humidity is
74%. Mean annual precipitation is 529.2
mil imeters, mostly taking place between late
September and late June.
Soils of study area are generally within Brown
Great Soil Group. Soil texture is mainly heavy,
namely clay and loamy-clay.
Primary land-cover categories in the study area
are Forests, Water bodies, Agricultural lands,
Non-vegetated areas. Almost 70* of the total study
area is covered by forest. Water bodies, namely
lakes and reservoirs is 0.3 %. Agricultural lands,
settlements and other areas constitute almost 29%
290
of the study site.
3.2. Data Acquisition and Preparation
LANDSAT-5 TM data were acquired
(Path 178 and Row 32) on 16
July 1984. Center geographic coordinates of the
image is N 40°20" and E 31°43’. They became
available on CCTs of BSO format (radiometricaily
and geometrically calibrated). Reference data used
to support the analysis was consisted of
identification by ground observation and recording
on maps with a scale of 1/25 000 the land-cover
type of necessary number of fields in the test
areas. Topographic land-cover maps with a scale of
1/100 000 were also used for geometric
rectification of the image and the verification
and accuracy assessment of the digital natural
resources classification together with 1/25 000
scaled maps.
Cloud-free digital
over the study area
Applying special algorithms available on the ERDAS
image processing system installed at the Remote
Sensing Laboratory in the Ankara University,
Agricultural Engineering Department, a subscene
covering the study area was extracted from TM
tapes and loaded on to floppies for further
analysis.
The extracted subscene was then rectified to a
state plane map projection. The implementation of
the rectification process was based on the image
and map coordinates of 14 control points uniformly
scattered throughout the study area. The map
coordinates were acquired by using a digitizing
table and the appropriate routines of the
available software. The set of the acquired
coordinates were used to compute the coefficients
of the transformation matrix using a least square
algorithm. The nearest-neighbour interpolation was
used to rectify the input image.
3.3. Field Work
provide indispensable support in the
remotely sensed data and are
obtained from actual
Ground data
interpretation of
helpful in the verification
site of study and in areas of particular interest
such as agriculture, forestry, water bodies and
other land-use categories (Gautam and Chennaiah,
1985) . Therefore ground data collection was
carried out in the study site. |t involved the
development of an overall systematic plan so that
all the selected sites could be visited. Intensive
study was carried out to collect data from the
max imum number of representative areas of
different land-cover type. Combining the
information of land-cover gathered by field work
with land-cover map on 1/100 000 scale,
percentages and acreage of each land-cover
category related to total area have been obtained.
3.4. Data Analysis
Preliminary visual interpretation for the
delineation of land-cover classes was performed on
1/50 000 scale screen display of LANDSAT
multispectral imagery with the help ofa false
color composite (Bands 4 red, 3 green and 2 blue).
In this study it was evaluated a number of biomass
transformations, or vegetation indices, in order
to emphasize the relative greenness of the land-
cover classes of interest. This evaluation was
done on a representative subset of test data, and
it was determined that the Radiance Ratio TM 4 /
TM 3 and the Normalized Difference Vegetation
Index Transformation [(TM 4 - TM 3)/(TM 4 * TM 3)]