Abstract: An approach for visualization of time series data. The approach for conveying time-series data may be a “heatmap timeline”. Rather than use a spatial dimension indicate a datum value for each timestamp, the heatmap timeline may employ hue, saturation, or value of color, and/or pattern and/or shading, perhaps shown within a geometric shape, to indicate the datum value along a timeline. Data values may be aggregated into one value indication. A tooltip may be pointed to a specific place on of the heatmap timeline to obtain a precise datum value at that place. More than one heatmap timeline may be on a display. Traditional line plots synchronized to the timeline may be added to the same display for comparison purposes. The heatmap timelines of various items within a hierarchical structure may be presented on a display. Data may also be presented in a mosaic fashion.