The image above is a snapshot of a Visual Fusion demographics application showing a map of census tracts shaded by median income. The top histogram plots what looks like a pretty-normal distribution of income across much of Michigan. The histogram beneath that shows the distribution of the unemployment rate. Hovering the mouse over any portion of the map or charts pulses the corresponding tract in the others concurrently.
Here are those same tracts shaded by relative unemployment rate. The topmost scatterplot shows the relationship between unemployment rate and the vacant house count per tract. The second scatterplot relates the unemployment rate to relative ruralness. The area of the census tract is used as a proxy to characterize how rural a tract is, generally. Larger tracts are assumed to be more rural, smaller tracts tend to be more urban.
sparkline inside a tooltip; as the user mouses about, the snippet of information that appears includes a neat little stripped down line chart.