Each graph shows the percentage difference between the number of supporters for Sen. Obama and the number of supporters for Sen. McCain. For example, a value of 10 means that 10 percent more people who were polled expressed a preference for Sen. Obama. Blue and red symbols indicate a lead of 7 percentage points or more for Sen. Obama or Sen. McCain, respectively.

The non-linear time scale shows an expanded view of the last 2 months of poll data, and a compressed view of the earlier data. To revert to a linear time scale, press the right mouse button over any graph and select the menu choice Revert to Linear.

To zoom in on recent poll data, click the left mouse button to mark a point in time. DataMontage will display a red vertical line. Then, move your mouse to the right of the red vertical line and right-click and select context menu choice Non-Linear X Axis / Right of 2 Intervals. DataMontage will display the earlier data in a compressed view, and it will display the recent data in an expanded view.

You can move your mouse over a symbol to see the exact value of the poll data and the name of the pollster. When you left-click over a graph, a red vertical time reference line is displayed in every graph to help compare and correlate data across graphs.

This interactive graphical summary was generated by the DataMontage data visualization system. It requires Java 6 or Java 7.

The poll data was provided by www.electoral-vote.com