  Cosmic microwave background (CMB) temperature anisotropies encode the history
of the universe, which manifest itself in the angular power spectrum. We test
the angular power spectra of small patches from the ESA $\textit{Planck}$ data.
Known variations in the power spectra from small patches reveal informative
details such as the gravitational lensing and the Doppler boosting effect. We
compute the relative shifts of power spectra via comparing patches selected
randomly from the CMB. We visualize the relative shifts on a full-sky HEALPix
grid (a feature map) and analyze the statistical properties on the full-sky
map. We find the regions contain the Cold Spot and the Draco supervoid have
large relative shifts to large scales. We also find a dipole on the generated
feature map comparing with simulations. We discuss possible ways to resolve
this dipole on the feature map, including foregrounds, solar dipole
systematics, and the uncertainty in our method.
