CREATING POPULATION DENSITY MAP

What is population density?

Population density is the number of people per unit of area, usually quoted per square kilometre or square metre or square mile units.

The population density is calculated using the formula, the total population divided by the land area covered by the population.

Importance

Cities are changing with time. Urban planning is mainly based on the density of the population not on the basis of the total population. The population density data shows us how densely populated an area is. Population density allows for a broad comparison of settlement intensity across geographic areas.

The physical factors that affect the population density include water supply, climate, relief, vegetation, soils and availability of natural resources and energy. Human factors that affect population density include social, political and economic factors.

Steps to prepare the district wise population density map.

Step 1: Downloading the shapefile of the districts in India

Visit the planning insights website and go to the open source data page, https://planninginsights.co.in/open-source-data.  

The interface of the website is shown above. Click on the Download button to download the file.

Download the “District Boundaries of India” data.

Step 2: Open the file.

Open ArcMap and click on the “Add Data” button.

Browse to the location where the file is downloaded and open the shapefile.

Step 3: Adding the district-wise population and area and calculating population density.

Now right click on the shapefile and open the attribute table. The attribute table contains the information about the shapefile.

For example, we are showing the population density of some of the districts in Maharashtra state only.

First, we have to calculate the area of the shapefile. For that, we have to convert the GCS (Geographic Coordinate System) to PCS (Projected Coordinate System).

Select Data Management Tools > Projections and Transformations > Project.

Select WGS 1984 World Mercator in the Output Coordinate System and click OK.

Now the projected shapefile will be loaded to the window.

The attribute table of the new shapefile contains shape length and shape area, but in metre and sq.m. We need area in square kilometres.

For that right-click on the Area field that we have created and click on the Calculate Geometry.

Change the unit into square kilometres and click OK.

The calculated area is shown in the above figure.

Now, we have to create another field named Total population in the attribute table.

Enter the population data into this field by clicking on the Start Editing in the Editor toolbox. 

You can use the Census 2011 total population data for better accuracy.

Here we have entered the total population in districts of Maharashtra.

After entering the data, click Stop Editing in the Editor toolbox and save the changes.

Next, we want to calculate population density in the table. For that, first, a new field (eg: Population_Density) should be added to the table.

Now, right click on the Population_Density field and click on the Field Calculator. A new window opens; enter the expression (Population/Area) in it by selecting the appropriate field names. Then click OK.

Now, the population density is calculated in lakhs/sq.km. Here we have only calculated population density for districts in Maharashtra.

Using these informations, we can create population density map of districts in Maharashtra.

For that select the data of Maharashtra district from attribute table and export the data.

The exported layer will be loaded to the window.

Step 4: Classification of data

Open the properties window of the shapefile and select Symbology.

Set the field Values as Population_density and classes to 5. Change the color ramp and click OK.

We can also create the map using dot density, symbols etc

Step 5: Creating Map

For creating map, change the view to Layout view in View option. Add Title, North arrow, Legend and Scale bar to the map from the Insert option.

The map looks like the above figure. 

We can save/ export the map by clicking Export Map in the File option.