The measurement criterion by square meters supposes the delimitation on a plane of the surface occupied by the concentrates. In a demonstration,the distance from the headland to the end or tail of the course is measured. To calculate the “useful area” where the mass of people fits, it is necessary to deduct the meters occupied by vehicles, trees, distances between groups of protesters, and so on. When the squared area is very dense, amaximum of 4 people per square meter(head plug, concentrations in small spaces, courtship stops). In other areas, 1 to 2 people per square meter are counted. When protesters are walking it is usually measured at 1 per m2. There are exceptions: for example, in case of rain,presupposes the existence of a protester under each umbrella.
Another interesting criterion is to countthe number of people including the width of each row, as well as the number of rows. These calculations are carried out at three or at least two different points along the route. The observer in this case must be placed in a narrowing or idling of the march. The start time of the march as well as the end time (passing time) and the stopping or idling times are also recorded. With this we will obtain the walking speed, which is usually 1 or 2 km / hour when the mobilization is massive.
