  We study the topological charge density distribution using the
two-dimensional $CP^{N-1}$ model. We numerically compute not only the
topological susceptibility, which is a spatially global quantity to probe
topological properties of the whole system, but also the topological charge
correlator with finite momentum. We perform Fourier power spectrum analysis for
the topological charge density for various values of the inverse temperature
$\beta$. We propose to utilize the Fourier entropy as a convenient measure to
characterize spatial distribution patterns and demonstrate that the Fourier
entropy exhibits nontrivial temperature dependence. We also consider the
snapshot entropy defined with the singular value decomposition, which also
turns out to behave nonmonotonically with the temperature. We give a possible
interpretation suggested from the strong-coupling analysis.
