National social distance guidelines differ, but all use one of three standards: one metre, one-&-a-half metres, or two metres. The table below shows how these social distances equate to radii and areas per entity, and invert to Cumulative High Density (CHD) map density thresholds (definable to two decimal places) in the far right column.
To create a CHD map compliant with assessment of a two-metre social distance, based on an extended spectral progression applied across a 15-minute period:
Note that the map defined above uses the Extended Spectral Progression value range, which has an upper bound of 15 minutes, meaning that any area in which the 0.32 people-per-square-metre threshold is exceeded for longer than 15 minutes will remain magenta. However, custom value ranges may be user-defined, where different timescales are needed.
Note also that Entity Density is constrained by proximity to obstacles, as well as other entities, so will rise in constrained space, even if there are no other entities nearby.
Lastly, social distance implementations differ, with some measuring stopping points two metres apart (excluding people's dimensions) and others including space for people, based on average or maximum dimensions. Those accounting for people's dimensions in their assessments should use the data in the table below to increase their target distances and map thresholds accordingly.
LEGION system entity size profiles were derived from publicly available anthropomorphic data. Circle diameters are the distances between the outer edges of people's shoulders, also called bi-deltoid widths.