This choropleth map encodes unemployment rates from 2008 with a unclassed scheme. This version uses a bipolar color scheme (see here a simple color example). For the classification there is an object "mapresso" with all the required parameters (as the colors and the class breaks at both ends of the value range). The class breaks are here calculated as 1.5 (zfact) standard deviations from the mean, the central threshold value is the mean.