A new Guide to Investigative Journalism
The Global Investigative Journalism Network (GIJN) in collaboration with iMEdD have co-produced the guide “Introduction to Investigative Journalism”, written by some of the world’s leading investigative journalists.
Estimating how many people attended an event, such as a protest or political rally, is often a contentious issue and a subject of public debate.
A typical example is the Tempi rally on January 26, 2025. Police reported that around 30,000 people gathered in Syntagma Square, while other estimates suggest more than 100,000 were in the center of Athens that day.
At iMEdD, we developed an experimental tool to help journalists—and anyone interested—estimate how many people might actually be in a given area. For example, if a 100-square-meter area has a density of one person per square meter, it could hold 100 people. This number varies depending on crowd density or the exact boundaries of the area being measured.
With the crowd-counting tool we developed, you can plot up to seven different crowd concentration areas on the map. After setting the desired density for each, the tool estimates the total number of people that could potentially be in the selected area.
For your convenience, we provide some ready-made examples in three squares – Syntagma Square, Aristotelous Square and Agios Georgios Square – each with a randomly assigned crowd density to help you understand how the tool works.
The tool has some limitations, which may affect its accuracy:
- When you draw an area on the map, the tool does not automatically distinguish between sidewalks and buildings. It therefore calculates the number based on the total area drawn, meaning that if the selected area includes buildings, flower beds or other obstructions, the result will not be accurate.
- Crowd density is not uniform across an area. For example, when you draw an area on the map, you should keep in mind that spaces with trees or steps will have a different density than open areas. This can lead to an underestimation or overestimation of the crowd in the selected area.
We recommend using the tool as a starting point for understanding an area’s potential capacity, but real-world knowledge is essential for accurate conclusions. It should be noted that this tool provides an approximate estimate rather than an absolute measurement.
This tool is a modification and extension of MapChecking, created by Anthony Catel, for iMedD Lab by Sociality. It is available as FOSS here.
