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STATISTICAL ANALYSIS OF CHANGES IN AGRICULTURAL LAND USE FOR A PART OF ANDHRA PRADESH USING SATELLITE REMOTE SENSING DATA

KrishiKosh

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Title STATISTICAL ANALYSIS OF CHANGES IN AGRICULTURAL LAND USE FOR A PART OF ANDHRA PRADESH USING SATELLITE REMOTE SENSING DATA
 
Creator BALAJI, THIAGARAJAN
 
Contributor NAGESWARA RAO, G
 
Subject STATISTICAL, ANALYSIS, CHANGES, AGRICULTURAL, LAND,
 
Description The present investigation was undertaken with a
view to study the changes in land-use and land-cover for
a part of Prakasam district in Andhra Pradesh using
satellite data of two different dates and also to see
how well remotely sensed data help in land-use and landcover
mapping. LANDSAT MSS data of 25.2.1975 and IRS
LISS-1 data of 17.10.1988 with comparable resolutions
were used in the study. Two study areas namely
Tripurantakam site and Hanumanthunipadu site with
varying landforms were chosen.
Preliminary visual interpretation for the
delineation of land-use categories was done for the two
study areas at 1:50,000 scale using LANDSAT diapositive
imagery of 1:1,000,000 scale of 1975, with the aid of
Procom for enlargement. This was followed by collection
of ground truth data by actual visit to the study areas
and verification of the interpreted map. Land-use maps
at 1:50,000 scale were prepared.
LANDSAT ( 1975) and IRS ( 1988-) computer
compatible tapes (CCTs) were analysed on the
sophisticated DIPIX computer system with"'the help of
training sets of each category collected during field
visits. Grey level histograms of the images and
statistical parameters for the selected training sets
were obtained from the computer system, which were
studied. The mean spectral reflectance values were
plotted in the form of spectral reflectance curves for
different land-use categories. Each study area was
classified into 6-7 land-use categories using two
classification algorithms, namely Maximum Likelihood and
Fast Parallelepiped. The same training sets were used
for the two algorithms. The area under each land-use
category was calculated for both algorithms for
monitpring land-use changes.
The classified maps produced by using the two
algorithms were assessed for accur~cy for the two study
areas and the two dates to determine which algorithm
performed better classification. Simple random sampling
technique wasused to select points from the maps for
verification with ground truth. The accuracy results
were given in the form of error matrices. The overall
percentage accuracies and individual category percentage
accuracies were computed. 80-90 per cent overall
accuracy was achieved with maximum likelihood
algorithm and only. 55-70 per cent with fast
parallelepiped algorithm. For most of the indiviqual
categories also, maximum likelihood algorithm showed
higher accuracies ·than fast parallelepiped algorithm.
Confidence limits for the map accuracy were calculated.
The known map marginal proportions were used to improve
the accuracy estimates.
Discrete multivariate analysis technique,
namely normalization of matrix . and coefficient of
agreement (KHAT statistic) for each matrix, was used to
compare and analyse error matrices of the two
algorithms. These methods showed that the
classif ~cat~on performance of maximum likelihood
algorithm was better than fast parallelepiped algorithm.
Tests of significance using KHAT statistic showed that
both algorithms were significantly greater than zero and
significantly different from each other. For individual
categories, three different accuracy values, namely
conditional coefficient of agreement, Short's index and
Hellden's index were calculated and compared. For these
measures also, maximum likelihood algorithm gave higher
accuracy values than fast parallelepiped algorithm for
most of the categories.
The changes in land-use between 1975 and 1988
for the two study areas were monitored. In the
Tripurantakam site, the area under irrigated crop land
and water bodies has increased due to irrigation
facilities provided by the Nagarjunasagar -~ight Canal.
On the other hand, the area under fallow land and upland
has decreased during this period. Further, unirrigated
crop land and salt-affected land were identified in
this site in 1988. In the Hanumanthunipadu site, an
environmental hazard in the form of a spread in pre·desertif
ication conditions was detected, as evidenced
by an increase in the area under sand between 1975 and
1988. The area under forest in this site has reduced
drastically during this period due to deforestation.
 
Date 2016-08-08T15:39:54Z
2016-08-08T15:39:54Z
1989
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/71611
 
Language en
 
Relation D3191;
 
Format application/pdf
 
Publisher ACHARYA N.G. RANGA AGRICULTURAL UNIVERSITY, RAJENDRANAGAR, HYDERABAD