This document discusses various methods for population forecasting that can be used by urban planners, including arithmetic increase, geometric increase, incremental increase, graphical, and logistic curve methods. It provides examples of applying these methods to forecast populations for the cities of Ahmedabad, Surat, and Vadodara in India for the years 2011, 2021, and 2031 based on past census data. Accurate population forecasting is important for urban planning purposes such as developing housing, employment, water and sanitation infrastructure, transportation, and recreational facilities for future population needs.

1. METHODS OF POPULATION FORECASTING
Faculty advisor:
Dr. J.E.M. Macwan
Sustainable Urban Planning Practices- (CE 632)
Prepared by
Kaushik Sheladiya
(P18UP004)
PG SECTION,URBAN PLANNING
CIVIL ENGINEERING DEPARTMENT, M.TECH-I, SEMESTER-II
2019
1

2. CONTENTS
 Introduction
 Objectives
 Factors affecting population forecasting
 Methods of Population forecasting
 Demographic Details of cities
 Forecasted population of cities(Ahmedabad, Surat,
Vadodara)
 Application
 Summary
References
2

3. INTRODUCTION
 This presentation deals with study of population
mathematics.
 It explains how various factors affects the population
growth and how to forecast population for different
cities.
 How urban planner can use that forecasted data for
planning of areas is also included.
 Population is forecasted for three main cities of Gujarat
for the census 2021 & 2031.
3

4. OBJECTIVES
 To estimate the growth rate of population in given city
 To compare different methods for estimating
population
 To estimate the carrying capacity of the city & plan the
city according to its carrying capacity
 To judge & implement the existing resource
management strategies based on the predicted
population
4

5. FACTORS AFFECTING POPULATION GROWTH
 Births Rate
 Deaths Rate
 Migration Rate
 Income & Education of people.
5

6. AERITHMATICAL INCREASE METHOD
 This method is based on the assumption that the rate of change
of population with time is constant.
 This method is suitable for large and old city with considerable
development. If it is used for small, average or comparatively
new cities, it will give lower population estimate than actual
value.
 In this method the average increase in population per decade is
calculated from the past census reports. This increase is added
to the present population to find out the population of the next
decade.
 Thus, it is assumed that the population is increasing at constant
rate.
 Hence, dP/dt = C i.e., rate of change of population with respect
to time is constant.
 Therefore, Population after nth decade will be,
Pn= P + n.C
Where, Pn = population after ‘n’ decades
P = present population. 6

7. GEOMETRICAL INCREASE METHOD
 In this method the percentage increase in population from
decade to decade is assumed to remain constant.
 Geometric mean increase is used to find out the future
increment in population.
 Since this method gives higher values and hence should be
applied for a new industrial town at the beginning of
development for only few decades.
Pn = P (1+ IG/100)n
Where, IG = geometric mean (%)
P = Present population
n = no. of decades.
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8. INCREMENTAL INCREASE METHOD
 Suitable for an average size town under normal condition
where the growth rate is found to be in increasing order.
 Increase in increment is considered for calculating future
population.
 The incremental increase is determined for each decade from
the past population and the average value is added to the
present population along with the average rate of increase.
Hence, population after nth decade,
Pn = P+ n.X + {n (n+1)/2}.Y
Where, Pn = Population after nth decade
X = Average increase
Y = Incremental increase
8

9. GRAPHICAL METHOD
 Populations of last few decades
are correctly plotted to a suitable
scale on graph.
 The population curve is smoothly
extended for getting future
population.
 This extension should be done
carefully and it requires proper
experience and judgment.
 The best way of applying this
method is to extend the curve by
comparing with population curve of
some other similar cities having
the similar growth condition.
9
Fig.1 Graphical
Method of forecasting

10. MASTER PLAN METHOD
 The big and metropolitan cities are generally not
developed in haphazard manner, but are planned and
regulated by local bodies according to master plan.
 The master plan is prepared for next 20 to 30 years for
the city.
 According to the master plan the city is divided into
various zones such as residence, commerce and
industry.
 The population densities are fixed for various zones in
the master plan.
 From this population density total water demand and
wastewater generation for that zone can be worked out.
 By this method it is very easy to access precisely the
design population.
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11. LOGISTIC CURVE METHOD
 This method is used when the growth rate of
population due to births, deaths and migrations
takes place under normal situation.
 If the population of a city is plotted with respect to
time, the curve so obtained under normal condition
looks like S-shaped curve and is known as logistic
curve
11
Fig.2 Logistic curve for
population growth

12.  Predict the population for the year 2011,2021 and 2031 from the
following population data by Arithmetic Increase method.
Solution:-
Pn=P + n.C
P2011 = 24,33,835 + 1x6,54,060 = 30,87,895
P2021 = 24,33,835 + 2x6,54,060 = 37,41,955
P2031 = 24,33,835 + 3x6,54,060 = 43,96,015
Year 1971 1981 1991 2001
Population 471656 776583 1497817 2433835
12

13.  Predict the population for the year 2011,2021 and 2031
from the following population data by Geometrical
increase method.
Solution:-
Pn = P (1+ IG/100)n
P2011 = 2433835(1+0.73)1 = 42,10,534 (as per census 2011;44,66,826)
P2021 = 2433835(1+0.73)2 = 72,84,224
P2031 = 2433835(1+0.73)3 =1,26,01,708
Year 1971 1981 1991 2001
Population 471656 776583 1497817 2433835
R² = 0.9965
0
500000
1000000
1500000
2000000
2500000
3000000
3500000
4000000
4500000
5000000
1971 1981 1991 2001 2011
Population Expon. (Population)
13

14.  Predict the population for the year 2011,2021 and 2031
from the following population data by Incremental
increase method.
Solution:-
Pn = P+ n.X + {n (n+1)/2}.Y
P2011 = 2433835+1x654060+315546 = 34,03,441
P2021 =2433835+2x654060+3x315546=46,88,593
P2031=2433835+3x654060+6x315546=62,89,291 14

15. DEMOGRAPHIC DETAILS OF CITIES
Details Ahmedabad Surat Vadodara
Map
(Location
&
Area)
Location Latitude23.03°N
Longitude 72.58° E
Latitude : 21.112°N
Longitude : 72.814°E
Latitude:22° 18′N
Longitude:73° 12′E
Area 466 Sq.km 326.515 sq.km. 300 sq.kms.
Population 55,77,940(Census
year 2011)
44,66,826 (Census
2011)
18,22,221(Census
year 2011)
Density 11,948Persons/Sq.Km.
(Census-2011)
13,680Persons/Sq.Km.
(Census-2011)
6,074Persons/Sq.Km.
(Census-2011)
15

16. Forecasted Population for Surat city by 2011,2021&2031
(Geometrical increase method)
Pn = P (1+ IG/100)n
P2011 = 2433835(1+0.73)1 = 42,10,534 (as per census 2011;44,66,826)
P2021 = 2433835(1+0.73)2 = 72,84,224
P2031 = 2433835(1+0.73)3 =1,26,01,708
R² = 0.9965
0
500000
1000000
1500000
2000000
2500000
3000000
3500000
4000000
4500000
5000000
1971 1981 1991 2001 2011
Population Expon. (Population)
16

17. FORECASTED POPULATION FOR AHMEDABAD CITY
BY 2011,2021&2031
(INCREMENTAL INCREASE METHOD)
Pn = P+ n.X + {n (n+1)/2}.Y
P2011 = 4525013+1x858338+1x323807 = 5707158
(as per census 2011; 56,33,927)
P2021 = 4525013+2x858338+3x323807= 7213110
P2031= 4525013+3x858338+6x323807=9042869
17

18. FORECASTED POPULATION FOR VADODARA CITY BY
2011,2021&2031
(ARITHMETIC INCREASE METHOD)
R² = 0.9955
0
200000
400000
600000
800000
1000000
1200000
1400000
1600000
1800000
2000000
1971 1981 1991 2001 2011
POPULATION
CENSUS YEAR
Forecasted Population for Vadodara
by 2011
Population
Linear
(Population)
Pn=P + n.C
P2011 = 14,91,045 + 1x3,41,348 = 18,32,393 (as per census 2011; 18,22,221)
P2021 = 14,91,045 + 2x3,41,348 = 21,73,741
P2031 = 14,91,045 + 3x3,41,348 = 25,15,089
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19. USE OF POPULATION FORECASTING
 Most of the important decisions can be taken about
major land uses and services
 Development Planning like housing, employment
etc.
 Design of water supply and sanitation scheme.
 Projection of labor force for estimating the future
production of goods and services.
 Population Projections by age for requirement of
future school enrolments.
 Future demand for, food, power, water, waste disposal &
transport etc.
 To estimate possible recreational demands
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20. SUMMARY
 Geometrical increased method is the method to
forecast population.
 From the population data urban planners are able to
design the different components of urban areas to
avoids failure of any system.
 Urban planners will be in position to take preventive
measures.
 It is useful to policy makers in the framework of
different urban & rural scheme.
“The cities occupy 2% of the earth’s surface, their inhabitantas
use 75% of the plantes’s resouces”- UN
 Ultimately it helps to create sustainable environment in
urban areas.
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21. REFERENCES
 Enrico F. and Tomasz Z. (2018), “Survey Sampling and Small-Area Estimation", An
international journal of Mathematical Demography, University of California,vol. 25,pp.
181-183.
 Franceso C. (2015), “Integrating Macro and Micro Level Approaches in the
Explanation of Population Change", An international journal of Demography, University
of California,vol. 69,pp. S11-S20.
 Ghosh M. and Jiyon M. (2018), “ Nonparametric Bays and Empirical Bayes Estimation of
The Population", An international journal of Mathematical Demography, University of
California,vol. 25,pp. 159-167.
 Hallie J. and Louis G. (1996), “Demography and Decision Making", An international
journal of Mathematical Demography, University of Nebraska,vol. 2,pp. 579-584.
 John C. (2013), “World Population Growth; Past, Present, Future", An international
journal of Environmental and Economics, London, vol. 55,pp. 75-82.
 Mauno K. and Jussi H. (2018), “Register Data in Sample Allocations for Small-Area
Estimation", An international journal of Mathematical Demography, University of
California,vol. 25,pp. 1-31.
 Rainford P. and Masser I. (1986), “ Population Forecasting and Urban Planning
Practices: Case Study", Journal of Environmental and Planning, England,vol. 19, pp.
1463-1475.
 Report on “ Understanding and Using Population Projections", Population Reference
Bureau,USA, 2001. 21

22. THANK YOU
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