Google Earth is a geographic information program that utilises superimposed images obtained by satellites and aerial photography. As part of a project conducted by the Center for International Earth Science Information Network at Columbia University, Google Earth has developed an add-on program that allows users to find the population of a geographic location. Using Google Earth to estimate population involves downloading the add-on, finding an address, measuring a target area and identifying population density on a legend. The data in this add-on was obtained between 2003 and 2005 and the population number you obtain will not be exact.
Download and install the latest version of Google Earth. As of 2010, this is version 5.
Download the Population Density add-on for Google Earth. This program will automatically install and launch.
Enter the address of interest in the "Fly to" box, located in the upper-left corner of the program.
Click on "Ruler" in the Tools drop-down menu. The Ruler dialogue box will appear on your screen.
Select "Miles" in the length field of the Ruler dialogue box.
Click on the centre of your address marker. A yellow line will appear, and the length field in the Ruler dialogue box will show how many miles this line represents. Drag your cursor away from the address marker until the yellow line represents one mile.
Note the colour of the map within your one-mile radius. Zoom out and locate the Population Density legend on the map.
Compare the colour of your target area to the legend. To find population, take the corresponding population density number and multiply it by the area of your target. Assuming your target is a circle with a radius of one mile, the area is approximately 3.142 square miles. Use this value as the area of your target when multiplying by the population density number.
If you have trouble measuring distance around an address, click on "Scale Legend" in the View drop-down menu. This will show a distance legend in the bottom-left corner of the map. Take a screen shot of your targeted area to help compare its colour to the population legend. On a Windows PC, this can be done by pressing "Ctrl" and "PrintScrn" simultaneously.