  A recent theoretical breakthrough has brought a new tool, called
\emph{localization landscape}, to predict the localization regions of vibration
modes in complex or disordered systems. Here, we report on the first experiment
which measures the localization landscape and demonstrates its predictive
power. Holographic measurement of the static deformation under uniform load of
a thin plate with complex geometry provides direct access to the landscape
function. When put in vibration, this system shows modes precisely confined
within the sub-regions delineated by the landscape function. Also the maxima of
this function match the measured eigenfrequencies, while the minima of the
valley network gives the frequencies at which modes become extended. This
approach fully characterizes the low frequency spectrum of a complex structure
from a single static measurement. It paves the way to the control and
engineering of eigenmodes in any vibratory system, especially where a
structural or microscopic description is not accessible.
