Where is the landscape in the city, when the landscape is everywhere? What is landscape when « men without qualities » – as defined by Robert Musil – find themselves thrown into an unknown city (Saint Petersburg)? What is landscape when a geographer (Laurent Matthey) and an economist (Christophe Mager) try to answer this question according to their city practices, always a little impregnated with disciplinary knowledge ? These issues raise ontological (what is it the landscape ?), epistemological (how to think about the landscape ?) and political concerns (what is collectively done when we generate landscape value?). We nevertheless tried to answer it practically : 1) by turning to a methodological principle borrowing at the same time from a landscaped transect (across town) and a situationist drift (crossing the city in all directions), 2) by using a technical mediation (a smartphone) likely to introduce a double framing and distancing effect and, 3) by defining some elementary formal constraints (a reflexive and critical dialogue anchored in disciplinary knowledge and sensibilities both different; a role play because the geographer will toughen the impressionistic side of his notations, whereas the economist will stress the apprehension of the reality through a priori categories).