MODELLING URBAN POPULATION GROWTH USING REMOTE SENSING

MODELLING URBAN POPULATION GROWTH USING REMOTE SENSING

CHAPTER ONE

INTRODUCTION

 

            1.1 Background of Study

Nigeria population is currently estimated at 192 million individuals with growth rate of 2.5% against the backward growth rate of the country economy (NBS, 2016). The consequences of population growth on the economic development of less developed countries and developed countries are not the same because the condition prevailing in these countries are quite different from those of developed economy. Therefore the body of literature on population growth in Nigeria has always emphasized either the negative or the positive effect. In every discussion, it is conventional to start with a definition of terms used in such discussion. However, population growths can be seen by a demographer as a change in the size of the population. But when this change occurs in such a way that it reduces the size of population, the demographer refers it as a negative growth but when it adds to the size of the population he regards it as a positive one. What we get from this concept is that population growth can be positive or negative depending on whether there is an increase or decrease in the size of a given population. Population whether positive or negative is derived from three demographic variables such as birth, death and migration rates.

Udabah (1999) Threw more light on this by adding that birth and death rates in underdeveloped countries are quite different from that of developed countries. Birth rates in underdeveloped countries are generally high, why those of developed countries are low. On the other hand, death tales are higher in underdeveloped nations. The higher rate of population growth is therefore a major characteristic of underdeveloped nations and is partly responsible for the rates of economic development.

Moreover, the population of any country constitutes the most vital component of its resource base. This aspect is based mostly on its size, growth rate, spatial distribution, demographic structure and quality in terms of level of education, fitness and social welfare. Population statistics are indispensable impute into the planning process in any area. To government issuing programmes for instance in the efforts of government in the developing countries to feed the people and also provide quality services for them are being frustrated by rapid population growth. This growth is attributable on the one hand to improvement in human survival associated with the application of modern medical science to health matters, better sanitation and immunization of children which have caused the death rate to decrease. On the other hand, so many socio-cultural issues have complimented the growth of population in Nigeria positively (Lee and Miler 1990, Rennne 1995, Ainsword, 2016).

Consequently, the world population has been increasing and the last two decades have been demographically unprecedented as it rose from 4.2 billion people in 1985 to 6.4 billion in 2010. Much of this occurred in the developing nations as their population grew from 3.7 billion to 3.1 billion as against that of developed nation which grew from 1.1 billion to 1.2 billion over the same period (United Nation, 2001).

Nigerian’s population is one of the fastest growing populations in the world and Nigeria is the most populous country in Africa, ranked the tenths as obtained from two major sources, viz the 1991 census and the Population Reference Bureau World Population Data Sheet. Obviously, the population of Nigeria is large which makes it a “giant” relative to the other Africa countries. The large population of Nigeria implies a large market for goods and services as well as large pool of human resources for development. However, the impact of population on development depends not only on the absolute size but also on its quality. The major function responsible for the rapid increase in the population of the country is the relatively high fertility level as portrayed by a total fertility rate of about 6.0 life – birth per woman in the 1990s having seen from theoretical and empirical view that the population growth is an impediment to the economic growth and development especially under developing countries. It is then important to answer this question, how detrimental is population growth to the economic growth? To answer these, we look into the interactions between population growth and any of the economic variables such as, population growth, unemployment, savings, interest, and inflation etc. So, in this research work, our demonstration of the impact of population on economic growth will be based on the study of the relationship between population growth, interest, unemployment and inflation. Now the question to answer becomes how those population growth influences unemployment? Since we are working on the impact of population growth on Nigeria, as whose population according the 2006 census was estimated to be at a growth rate of 3%, our limitation of this study would be on the Nigeria GDP (Gross Domestic Product) or GNI (Gross National Product) versus the population growth rate of Nigeria (Noko, 2016).

Nevertheless, economic growth is the GDP OR GNI divided by the total population of the whole country. This measures the level of output in the economy. This equation implies that if population is rapidly growing, the economic growth will reduce marginally and people income will also decrease. So according to the finding, GDP can be improved that is GDP per capital by checking the population growth rate through birth control, death rate, migration and some other economic variables and demographic variables.

This study is on the application of Remote Sensing (RS) and Geographic Information System (GIS) Techniques to the examination of the nature of population growth in the northern district of Chanchaga local government area from 2000 to 2017.  Population influx to towns and cities often result in urban expansion and sprawling, pushing the urban environment influences into the adjacent rural lands with attendant changes in population types, intensity and landscape quality.  That is how Chanchaga local government area, a former political regional headquarters for more than half a century, grew.  Field observations show that its expansion has had great impact on the surrounding rural lands.  Scanty records both in maps and written documents were available to show the nature of the changes that had taken place.  Thus, reconstruction of changes in population becomes difficult with probable large errors and speculations.  Yet, there is a dire need for an understanding of the dynamics of populations on the urban periphery for effective planning, management and provision of utilities.  Nowadays, earth-mapping technology offers good opportunities for investigating population changes that have taken place in the past.  Hence, this study investigates the population growth in Chanchaga local government area using Remote Sensing and Geographic Information System Techniques.

 

            1.2Statement of The Problem

Rapid population growth has been a major feature of developing countries with concomitant development of large urban centers in population and areal extent.  However, in the Nigeria, urbanization predated the advent of the Europeans.  Large traditional cities were already in existence e.g. Lagos, Ibadan, Abeokuta, Ijebu Ode, Ondo, Benin, Oyo, Ogbomosho, Ilorin, Maiduguri, Kano, Sokoto and Zaria  (Church, 1965) and (Hance, 1970).  With the coming of the British rule, regional administration and economic development, migration from rural areas to towns/cities increased.  Thus, increase in growth resulted in urban sprawling (Mabogunje, 1968).  Rural-urban movement of people demands provision of accommodation which in turn results in expansion of the urban environment (sprawling) into adjoining rural lands.  In the case of traditional cities, where the city-core would have been effectively occupied with little “open space”, with a high demand for accommodation at a rate greater than the town planning engineers can provide, the urban periphery is bound to become the target area for squatter dwellings, land development speculations and confused population patterns.  Hence, the term “problem zone” is used to describe such a situation.  Therefore, there is the need to understand population dynamics in the rural lands adjacent to urban centres.  For example, the knowledge of the relationship or equilibrium existing among different elements in the urban peripherial ecosystem will help in monitoring the effects of changing populations.  In many Nigerian cities, there is no knowledge or records of what the urban peripheries were like.  Here, Remote Sensing and Geographic Information System have high potentials and applications. It is the focus of this study.

1.3Research Aim and Objectives

Objectives

1. To Examine the processes and factors that facilitates urban growth
2. To identify urban growth pattern
3. To predict future urban population growth

Aim

To model urban population growth in chanchaga local government using remote sensing and GIS

 

1.4 Research Questions

1. What are the processes and factors that facilitates urban growth?
2. What is urban growth pattern?
3. How to predict future urban population growth?

 

1.5 Significance of Study

The rapid growth of Chanchaga local government area has resulted in (i) availability of infrastructural facilities in Chanchaga local government area (ii) rural -urban migration in Minna metropolis (iii) changes in population types with attendant conflicting interests through the expansion of the urban environment.  Thus, the Minna city planners and engineers are always struggling to cope with the rate of city expansion.  Resolutions of problem of population changes and conflicts have often resulted in confused/poor urban landscape (Abiodun, 1998).  Some of the problems manifest in form of erosion, flooding, poor provisions of utilities and service; poor sanitation and urban environmental health risks.  Besides, attempts being made to solve these problems are at best “crisis management” in approach with the risk of losses of lives and property.  A study of past condition of what the adjoining rural lands were using RS and GIS technology will certainly provide a first step towards effective solution to poor urban environment problems.  It may also give insight into effective urban land management.  The earlier population maps (e.g. Max Lock 1957; 1967) were based on the conventional land/field surveying which tend to propergate and accumulate errors; and because of limitation in areal coverage they are full of generalizations.  On the contrary the maps constructed and population demarcated using photogrammetry (which aid population interpretation through the land/field surveys) are far superior in precision and details as represented on air photos and imageries.

1.6 Scope of the Study

The study was aim at modelling the population growth of chanchaga local government area of Niger state with particular reference to Minna Urban area which is the state capital. The study used both remote sensing and GIS to predict the population growth of the entire Chanchaga local government area which include villages, town and popular Minna which is the state capital.

 

1.7 Definition of Terms

It is necessary to state here that there is a need for a short section on definition of terms used in this proposal. Since the nature of the subject demands it.

1. Parallax: The apparent displacement of the position of a body with respect to a difference in point system caused by a shift in the point observed.  Parallax bar (or stereometer).  A measuring device containing a micrometer by which the separation of two index marks can be changed to measure parallax difference in terms of height on a stereoscopic pair of photographs.
2. Stereoscopic View: The orientation of photograph when properly positioned to give a 3 dimensional view of X, Y, and Z directions.
3. Model: A stereoscopically viewable terrain, as at photography. It is formed from 6 standard points 1,2,3,4,5,6.  Each of the points (1,3,5) and (2,4,6) from a cross section. (Figure 2).
4. Standard points: For projective geometry, the internationally accepted points where the orientation can take place in order to obtain a stereo model.
5. Overlap: An overlap is made up of similar terrain features viewed from two aerial photographs taken from two exposure stations.
6. Colinearity condition: Linear nature of rays of light from source to the object. It states that the “exposure situation”, the image point and the object on ground are on the same straight line.
7. Coplanarity condition: Expresses the range at which the stereoscopic model lies within a plane. It states that the two exposures station, the two image points and the object point must lie in a plane.  (Figure 3).
8. Inner orientation: This is the resolution of the original bundle of rays that made the photograph. Practically, it is carried out on instruments by setting the principal distance, centering the photographs (diapositives), setting correction clamps (etc).
9. Relative orientation: This is also called Y-parallax removal. It is defined as the procedure of intersection of conjugate rays (pair of rays intersections on the terrain from two exposure stations).  It is proved from projective geometry that if 5 of such conjugate rays are made to intersect at any 5 of the 6 standard points, stereco model is formed.  (the sixth point is used as a check).
10. Absolute orientation: This is often referred to as scaling and levelling of the model. It is the procedure of obtaining the orthogonal projection of the various heights of points on to the terrain.
11. Floating mark: A black measuring dot on the instrument for measurement (of planimetery and height).
12. Fiducial Marks: Marks at the edges of an aerial photograph used for a proper centering of the photo (diapositives) on the X, Y plate carriers.
13. “Dot Grid” (Template) overlay: Dot marks in a square or rectangular systematic grid on a transparent overlay for the purpose of identifying and measuring of population areas. The spacing of the dots may be expressed as grid density or number of dots per hectare or square kilometre.
14. Polar planimeter: An instrument used to measure the area of any figure by passing a tracer around its boundary and recording the area so encompassed. The measurement uses the principles of vectorial angles and radius vector.
15. Weight apportionment technique: Weight is the measure of relative reliability worth of a quality as compared with other values of the same quality comparable gratitude.
16. Photogrammetry: This is the art, science and technology of taking geometrical measurements by means of photographs.
17. Air photo year: The year a photograph was flown at a given scale.
18. Photo mosaic:An assemblage of aerial photographs whose edgeshave been cut and matched to form a continuous photographic

representation of a portion of earth surface.

 

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