Abstract: Methods and systems are provided that determine data characterizing spatial variation of vibrational dysfunction (such as HFTO) along the BHA of a drilling system. In embodiments, such data can be determined from a minimal set of measurements of any or all of four variables that include: vibration amplitude; vibration wavelength; vibration frequency; and the axial position of the first vibrational node. In embodiments, such data can be determined from measurements of vibration amplitude and vibration frequency of a BHA at two fixed positions along the BHA (e.g., with two sensors offset axially along the BHA). In other embodiments, such data can be generated from the estimated position of the first vibrational node and measurements of vibration amplitude and vibration frequency by a single sensor disposed at a fixed axial position along the BHA.