Despite working in different cities and for many years in isolation from each other, Whyte and Gehl both came up with broadly the same three factors as being crucial for good public spaces:
– Social encounters
Gehl, J (2001) Life Between Buildings: Using public space. The Danish Architectural Press [5th Edition, originally published in 1971]
Whyte, W.H. (1980) The Social Life of Small Urban Spaces, Project for Public Spaces.