  In this paper we define a class of Boolean and generalized Boolean functions
defined on $\mathbb{F}_2^n$ with values in $\mathbb{Z}_q$ (mostly, we consider
$q=2^k$), which we call landscape functions (whose class containing generalized
bent, semibent, and plateaued) and find their complete characterization in
terms of their components. In particular, we show that the previously published
characterizations of generalized bent and plateaued Boolean functions are in
fact particular cases of this more general setting. Furthermore, we provide an
inductive construction of landscape functions, having any number of nonzero
Walsh-Hadamard coefficients. We also completely characterize generalized
plateaued functions in terms of the second derivatives and fourth moments.
