Abstract:
There is no doubt that Dhaka city i. growing bUl in which direction and what rale thaI
is the main COnCllm.There is also the question how urban growth is influencing the
different landuses. Thi. study was initiated to find the answer to these questions. In
today. faSI growing pace, the be.t available option to to understand the phenomenon
ofuman growlh is the application of Remote Sensing techniques in amulgamation of
GIS methods.
The study made an attempt 10 understand the relation.hip between the spatial and
temporal trends in urbanization and vegetation pattern with tho u.e of Remote Sensing
methods. Multidate Landsat images of 1993,1996,199,2003 and L1SS III image of
20117have been used to delineate tho iancover of Dhaka Metropolitan Area into <even
c!asses;Water, Builtup area, Baresoil, Grass typo vegetation, Tree type vegetation,
Crop type vegetation and Wetlands. In this study only two of the widely used
approacl1es i.e. Maximum Likelihood method (a supervised oIassifioation approach)
and NOVI (a vegetation index based approach) was explored. Aouracy assessmenlof
the oIassified images with thaI of ground !ruth dala showed that tllOqualily of results
obtained through maximum likelihood oIassification method were much beller than
the NDV! derived outputs.
It W,," found through lancovor analysis that over the years, builtup area within !he city
boundary has expanded from 23% to 47% from 1993 to 2007. Consequently, other
lype of landuses have decreased within a span of 14 years from 1993 02()()7, such as
vegetation area (including grass, trees and crops) 58% to 400/0, wetland and
waterbodics 14% to 8.7%. TIICdecrease in tree type vegetation is prominent reaching
10% in 2007 from 17% in 1993. The spatial paltern of dmnges in both urbanization
and vegetation area is sporadic in lUll"'e. The image analysis shows that the areas
with vegetation (gill", tte.s), bare soil, agricnltural land (area with crops),
walert>odies and wetlands have been convened into urban areas and lhis trend is still
continuing. If such a trend of urbanization at the cost of reduction in velletation,
waterbodies continues ignoring any planning consideration of keeping green space,
preserving wetlands then Dhaka city's environmenr will becomc unmanagable
oau.sing deterioration to the qualily oflife of city dwellers.
