The technique of electromagnetic spectrum map-ping enables the revelation of spatial distribution patterns within the electromagnetic environment. Precise visualization of the location information of electromagnetic spectrum signals contributes to enhancing spectrum utilization efficiency and system robustness. This technique finds wide applications in the fields of communication, navigation, radar, and other systems related to positioning and signal processing. It serves as a crucial means for modeling and simulating complex electromagnetic environments, playing a vital role in ensuring the accuracy and reliability of electromagnetic environment modeling and simulation. In this paper, we first introduce the technical background and knowledge related to electromagnetic spectrum mapping, analyzing the principles and current research status of electromagnetic spectrum mapping technology both domestically and internationally. Subsequently, we delve into a comprehensive analysis of high-precision electromagnetic spectrum mapping techniques based on sparse sampling, emphasizing potential solutions. Finally, we summarize the challenges and future directions faced by current electromagnetic spectrum mapping techniques, providing insights into their prospective trends and applications.