VDV offers the Overlay Graph tool which is an outstanding analyzing tool for presenting a single sensor data such that daily trends (or regular trends) show clearly. Using the default 1 day scale on the X-axis a total of 28 days of sensor data will be plotted, each day overlaid on the others. This allows users to spot trends or deviations which repeat itself at regular intervals. Apart from the default 1 day scale users may select other scales for the X-axis, e.g. 1 hour, 12 hours, 1 week, 1 month, 3 months and 1 year.