“…S PECTRUM cartography [1], [2] has been introduced to construct radio maps [3], [4] of a certain channel metric [5], such as power spectral density (PSD), received signal power (RSS) or channel gain over a geographical region of interest based on measurements collected by the radio frequency (RF) sensors deployed within the region [1] for years. Since radio maps comprise the critical information [6], [7] of RF environment across multiple domains [8], e.g., space, frequency, and time, they have been widely utilized in applications of wireless communications including network planning, interference coordination, dynamic spectrum access, and spectrum surveillance.…”