What is urban planning?

I consider urban planning as a communication between the designer (the architect) and the user (the citizen). If this communication flow smoothly, the designer has accomplished the goal. In the other case any mismatch of perception the user can experience should provide a deep insight to the designer.

From Lynch, The image of the city, p. 28:
“… environmental image is the result of a reciprocal process between the observer and the environment: environment suggests differences and relations, the observer, with great adaptation, and with personal reasons select, organise and give meaning to what s/he sees. …”