One of the most important issues with most maps showing geolocated data published online today, is the fact that this data is shown based purely on the physical location and direct frequency of certain phenomena. As a result, while a neighborhood might seem less safe because it features a lot of red dots, it might simply be a highly trafficked and densely populated area, and much safer than it appears.
See UK [seme4.com] attempts to tackle this problem by placing an abstract visualization technique alongside the traditional map view to provide an overview various data attributes, such as crime, transport and education statistics. All data is normalized by population amount or area size, or shown as raw numbers.
The circular visualization is centered on a specific chosen region and features a "pie-chart" graph that shows how that region compares with similar regions around it. Color indicates the "worst" (red) and "best" (green) areas from those shown. This pie-chart is used in preference to coloring the map itself, as a colored map typically confuses some of the map features with the data that is visualized. Users can navigate by clicking on the pie-chart or the map, and explore the data using their preferred view.