Unevenly spaced data records are received over time. A smoothed graphical visualization has a plurality of discrete rings to allow for detection of periodical patterns in the data records, where the discrete rings correspond to plural time periods and contain pixels representing values of an attribute of the data records. Visual indicators are assigned to the corresponding pixels, where a first of a visual indicators for a first time interval that is missing a data record is based on aggregating values of the attribute of neighboring data records, and where a second of the visual indicators for a second time interval having multiple data records is based on aggregating values of the attribute of the multiple data records.