In order to deeply understand characteristics of wide area measurement(WAM) information, analog analysis method is used to explore reason why WAMS theory research results are difficult to be converted into practical applications. Firstly, based on big data 4V features of information theory, a logical structure for judging big data is proposed. Then, generation process, structure and association relation of transient data, dynamic data and event identification data are analyzed. With a WAMS example, analogy ...