131 million were used in conjunction with
the topographical map of scale 1:50,000
prepared by Survey of India (SOI). The
imageries used were panchromatic black
and white Band 2 (0.52-0.59 um), Band 3
(0.62-0.68 um), Band 4 (0 2050.06 um) and
False Colour Composite (Band 2,3,4) hav-
ing Scene centre 24 47!20 North Latitude
and 92^755'22"East Longitude. The date of
acquisition of the imageries was 8 Novem-
ber, 1989 at O9 hr- 49 min- 16 sec. The
details of topographic sheets used for
the purposeare given in Table l. The
imageries and FCC were studied by placing
them on light tracing table and viewing
through a hand magnifying (X4) lens.
ME THODOLOGY
The primary objective of the study was
to delineate the land use and forest cover
of the study area on the basis of the data
available from the topographical maps and
remotely sensed data of the area. The
ground truth for analysis of IRS imageries
was essentially derived from topographical
maps on the basis of 'Convergence of Evi-
dence' principle. The broad methodology
adopted for the study is outlined as
below:
l. Collation of data of the study area in
the form of maps and IRS imageries.
2. Analysis of the available topographical
maps (a portion of the whole scene) and
development of forest cover and land
use maps in the scale of 1:50,000 on
the basis of the same.
3. Analysis of the imageries of the study
area in relation to the 1:50,000 maps
and development of interpretation keys
for the land use and forest cover cla=
sses adopted for the study area.
4, Analysis of the whole scene on the
basis of the above data.
9. Cartographic presentation of the analy
sed land use data.
INTERPRETATION
The assessment of the imagery and its
interpretation involved the comparison of
spectral response of each type of imagery
with the respective areas of land use
which were easily identified from collat-
eral materials. The key characteristics
are listed in Table 2. Imageries used
for visual interpretation are thus divided
into three broad class I categories. The
level I categories are divided into a
number of level II classes using the in-
terpretation elements tone, texture, co-
lour, size, association and patterns.
These interpretation keys are designed to
facilitate the rapid and accurate identi-
fication of features as imaged in IRS im-
ageries. It is also used as a record to
correct interpretation of land use in
less obvious areas.
OBSERVATION
The land cover of the scene is classi-
fied into three broad level I classes as
water bodies, forest cover and built up
areas. Water bodies are divided into
level II classes as : river, stream, lake,
dry river. The forest cover is divided
into three level II classes : dense fore-
St, medium forest and tea garden. Lastly,
the built-up areas are divided into habi-
tat, paddy field, tea garden, road and
railway. The following observations
were made on different classes and sub-
classes.
Water bodies
Water bodies are very prominant in
band 4 and FCC imageries. The delineati-
on of river and stream of high order can
be done most easily from band 4 due to
the distinct dark black tone and pattern.
However, in some cases especially near
heavily built-up areas the FCC coupled
with Band 3 imageries helped in exact
delineation of the feature. In some cas-
es band 2 imagery supplemented the deli-
neation. However, lakes are best delin-
eated from FCC due to the distinct colour
with respect to adjoining features. The
intensity of tone and colour found to be
depended on the depth of water. The larg-
er the depth the greater is the intensity
In case of perfectly dry river/stream or
meanderings, the intensity of tone is
very low distinguishing it from adjoining
water bodies.
Forest cover
The forest cover of the scene could
readily be distinguished and tentative
delineation could be done easlly from FCC
TABLE le Details of Topographic Sheets (prepared by SOI) Used.
Sl.No. ^ Map Sheet No. ^ Scale | . Centre Coordinates ^ ^ Year of ^ Edition
em ou ^ Am am m mom oem m dee m om e um tes cd am en North ... . East. . . survey _ and year
1 83D 9 1:50, 000 24952:30" . 92937'30" 1972-73 1st/1977
2 83 D 10 1:50,000 24937 *30^ 92937 130" 1972-73 1st/1975
3 83H 1 1:50,000 24952:30" 93%7*30" 1971-72 . 1st/1974
_4_ 883 H4 7) ::1350,000 25%07'30” 93°07*30" 1971-72 1st/1974
"ms 8 AY ANY d e rm
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a C£, C1 4 MN 1 AS
AS
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