Industrialization and development of technology have
caused rapid changes to land and contributed towards urbanization. Villages and
small cities are being converted to urban areas and into towns frequently these
days. Similarly, over the last few decades developed areas and urban sites in
cities and towns have been expanding in Bangladesh at a significant rate. Establishment
of industries and other landmarks have contributed significantly towards this
massive outburst and expansion of developed areas. To add to that there is also
better living standard and easier lifestyle in the cities. Therefore
urbanization is happening continuously. At the heart of this expansion in Bangladesh,
lies the city of Dhaka. Most of the outward expansion in terms of development
have happened centering Dhaka. The urban growth rate has risen up massively
since the last 15-20 years.
Bangladesh has seen a massive population outburst in the
last few decades. Dhaka is at the core of this rapid rise in population. Currently
about 2 billion people live in the city of Dhaka. To cope up with this
increasing number of population various other changes has been happening. To accommodate
a population this big the infrastructure and land use has also seen rapid
development. Social development, better financial chances and better lifestyle
have been the most intensive and leading factor towards change in land use. The
fast development has also caused changes in all the domains for this particular
town. Number of markets, industries, airports and different other establishments
have increased in Dhaka which has attracted even more people in this town and
as a result changes in land use is happening everyday by leaps and bounds. All
these influential factors have made rapid changes to Dhaka in geo level.
In this context remote sensing imagery and concepts can
come in handy. Terabytes of satellite image data are generated everyday with
all the satellites that have been launched to monitor the earth from different
criterion. All these images illustrate the condition of built up areas,
vegetation, water bodies and of various other natural and man-made entities.
Using satellite based images for land cover analysis and classification provide
promising results and enables to perform detailed study on areas that otherwise,
would not have been possible.
To perform the analysis based on the satellite image a reliable
work flow and model had to be designed. This workflow consisted of multiple
measures and decisions based on which the information had to be obtained from
the image. This extraction of information from the data can sometimes be
difficult and time consuming. Therefore, the goal was to design a general pattern
for analysis of the images which can later on provide important details in
terms of the changes and development of the land use.
Thus. The objective of this study is to study and
interpret the satellite images of the study area. By performing this analysis
the various measures for different types of lands and can be generated. This
approach uses various remote sensing techniques and algorithms. The interpretation
was performed for various years spanning over 3 decades. This allows to have a
clear picture of the changes that are occurring and also provides a more
accurate representation. Finally, it generates a model representing the growth
patterns and the most densely urbanized areas for Dhaka.
The study area chosen for this study is the Dhaka district.
Dhaka city is the capital of Bangladesh. It is the largest city of Bangladesh
and accommodate the lion’s share of this huge population the country. After the
1990s the urbanization and industrialization has begun enormously in this city.
The rapid development of infrastructures and multinational companies led to the
overall development of the town.
All these factors played the role of catalysts for
attracting people from all over the country to migrate to Dhaka. All the socio
and economic factors played a key role too. As people started migrating to
Dhaka the land use change has been significant. The reduction of trees and
plantation is pretty much visible with naked eye. High raised buildings and skyscrapers
are a common scene now on every block of the city whereas there had been a
scarce number of high raised buildings only 20 years ago.
Besides construction of houses for this large number of
people the city needed to provide more land to the countless industries and mills
that have been established lately. They are more often located at the outskirts
of the city, near the rivers where it’s easier to commute. As a result, the
rivers have been overused and in some cases they are filled up. Not only the
rivers, many water bodies, such as small lakes and ponds are frequently filled
up to build houses and markets. Many trees have been cut down to build roads
for the rising number of cars in this town.
All these factors are influential for conducting a study
for analyzing the patterns of land use for the district of Dhaka. Another
objective is to monitor and figure out the changes across multiple decades and
where the changes have been maximum.
Remote sensing is commonly known to be the field that
deals with obtaining information about the surface of the Earth from a distant
place. The process is accomplished by sensing and recording reflected and
emitted energy. After that, that information can be processed analyzed and
applied for further use.
Mostly in remote sensing, the process involves interaction
between incident radiation and targets of interest. Remote sensing also uses
non imaging sensors and involves sensing emitted energy through different
techniques. The steps involving remote sensing can be broken down into different
The first requirement for remote sensing is to have a
constant energy emitting source. In our case, it’s the sun. Sunlight emitted
from the sun directly falls on the lands and water bodies. The latter phases
work after based on the reactance of the objects to this energy coming from the
As the energy from the sun travels to reach earth it has
to travel through the atmosphere and the different levels of it. As it goes
through it it, it interacts and radiates energy through it. The same process is
repeated while it returns after being reflected from the target object from
earth before reaching the satellite.
After reaching the area of interest the energy interacts
with the target object. After that the target object reacts to it, or emits