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Title
Proceedings of the Symposium on Global and Environmental Monitoring

So far IRS-1A has provided more than 2 lakh high quality data products of which
50,000 products have been effectively used in various applications of natural
resources, cartography, environment, engineering applications and coastal
oceanography. The data products are available in a variety of formats, ranging from
70 mm "quick look" film products (level 0) to user-specified digitally enhanced
special products (level 4) (DOS, 1989).
1.3 Information content and planimetric fidelity of IRS-1A data
Analysis were carried out to compare the information content of IRS LISS-II data
with SPOT and Landsat-TM bands. Statistical techniques viz., Entropy, Principal
Component Analysis and Correlation Analysis were performed. The results indicate
that (i) with respect to Entropy and percentage of information content for visible
channels of LISS-II data was found marginally superior to the SPOT and TM data and
with respect to NIR channel data, all the three data sets performed equally (ii)
correlation analysis indicated similar correlation between bands of all the 3
sensors (iii) PC results showed that information content in PC-1 of LISS-II was
higher (81%) than the information content of PC-1 of SPOT (67%) and PC-1 of TM data
(74%) (Table 2 & 3) (Bhan, et.al, 1989).
TABLE - 2 : ENTROPY AND PERCENTAGE OF INFORMATION
Sensors
Blue
Spectral Channels
Green Red NIR
Maximum possi
ble Entropy
SPOT-XS
1.99
4.33
4.72
7.99
(49.94)
(54.19)
(50.07)
LS-TM
4.56
3.9
4.54
4.85
7.99
(57.07)
(48.81)
(56.82)
(60.8)
IRS-1A
4.54
4.26
4.96
4.17
7.00
(64.86)
(60.86)
(70.86)
(59.57)
TABLE - 3
: MATRIX OF CORRELATION COEFFICIENTS
Sensor
Bands
1
2
3
4
SPOT-XS
1
1
2
0.96
1
3
0.09
o
0
1
1
-
LS-TM
1
1
2
0.90
1
3
0.91
0.95
1
4
-0.25
-0.08
-0.21
1
IRS-1A
1
1
LISS-II
2
0.97
1
3
0.92
0.94
1
4
-0.19
-0.04
-0.11
1
In the field of cartography it has been observed that LISS-II data with regard to
planimetric fidelity is as accurate as Landsat TM and SPOT. The rectified resampled
IRS LISS-II is found useful as a stereo-mate with high angle SPOT data. For the
purpose of map updating, it is found 75% of the roads could be transferred on
1:50,000 scale using IRS-1A LISS-II data. (Kesavaswamy, 1988, Dutt, 1988, Rajashree,
1988, Srivastava, 1988). Thus information content of the IRS-1A LISS-I data was
found comparable with Landsat MSS and Landsat TM with comparable spectral bands
data, the clarity and sharpness of features are found better on IRS-1A data due to
better radiometric quality and higher S/N ratio of the IRS-1A data.
2.0 APPLICATION POTENTIALS OF IRS-1A DATA
With such high quality of data available from IRS-1A sensors, numerous application
studies have been carried out. The potential applications of IRS data has been
tested for a wide range of natural resources applications including agriculture,
cartography, environment, coastal oceanography, flood management, desert
advancement, river morphology etc. Presently 70% of the user demands in India are
met through IRS-1A data and it is constantly on the increase. The results presented
herein are based on the case studies carried out during the last two years to
evaluate the suitability of IRS-1A data with that of Landsat MSS, TM and SPOT data
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