Each station on the London Underground network was used
as a survey point to provide a robust dataset for representing
Greater London in terms of geographical distribution and
population density, having a combination of urban (in the
center) and semi-urban (in surrounding areas) characteristics.
Measurements were taken at each of the 270 stations (from a
randomly chosen exit, at street level and a height of 1.6 m).
To provide traceability and for use as a historical reference,
time stamps and GPS locations were recorded. In addition,
measurements were taken inside a building at Imperial College
London (ICL), to represent a typical office block within an
urban environment.