Methods, user interfaces, systems and computer readable media for visualizing data to facilitate analysis of the data. Mass data values are provided for a sample having been separated into portions according to a first characteristic of the sample, the slices having been processed to provide the mass data values of members of the sample occurring in the portions. A plot of the mass data values is displayed on a first axis versus the portions on a second axis of the plot. A mass data value of a member may be selected on the plot, and all mass data values occurring in the portion in which the selected mass data value is located are displayed using first visual indicators that are visibly distinct from visual indicators used to display data values occurring outside of the portion in which the selected data value is located.