Simple graphical method for population forecasting is requires an experienced person for the appropriate judgment in curve extension.
As this method depends on the skill and judgment of the person extending the curve, a very rough estimate is known and the result may contain errors.
In This Article
Simple Graphical Method of Population Forecasting
The steps of estimation of population by simple graphical method are described below:
1. Plotting P vs T graph: A graph is plotted taking time on Y-axis and population on X-axis to an appropriate scale.
The time is taken at an interval of a decade for which the population is known from the census data. Hence, census data of previous few decades is essential for this method.
2. Population Curve: The population vs time is plotted and all the dots are joined to obtain the population curve up to the present period.
3. Extended Curve: The graph is then extended smoothly up to the design period following the shape of the plotted curve. The extension requires a keen judgment, which comes from experience.
One of the ways to extend is by comparing the population curve of some other town/city which shows similar growth characteristics.
4. Approximate Estimate: From this extended curve, the future population is then derived. This estimate is an approximate value.
Population Curve from Simple Graphical Method
The curve obtained by plotting the population vs time graph with time on Y-axis and population on X-axis is called population curve.
Simple Graphical Method Example
| Year (T) | 1971 | 1981 | 1991 | 2001 | 2011 |
| Population (P) | 40,65,698 | 62,20,406 | 94,20,644 | 1,38,50,507 |
Step1: Given Data:
Population (P) at corresponding years (T) is given
Step2: Plot the Graph taking T as Y-axis & P as X-axis and obtain population curve:
Step3: Extend the population curve smoothly following the former shape:
Step4: Estimate the population value (Pn) corresponding to the year n from population curve:
In this case, the estimated population will be approximately 1,80,00,000
Summary
Simple graphical method for population forecasting requires an experienced person for the appropriate judgment in curve extension. One of the ways to extend is by comparing the population curve of some other town/city which shows similar growth characteristics.
FAQ
What is graphical method of population forecasting?
- The time is taken on Y-axis and the population is taken on X-axis.
- After that, a graph is obtained between population to its corresponding time.
- Then the obtained points are joined to obtain the population curve.
- Population curve is then extended smoothly and carefully.
- The population is then noted down for the needed year.