MAPresso classification with d3.js

This test for the MAPresso classification scheme in a d3.js context is based on a blogpost by Gabriel Florit (Dec. 14, 2011, "Choropleth classification systems"). He compared different classification schemes, I extended it by the unclassed scheme typical for MAPresso. The MAPresso specific code is just to show the feasibility of the concept. There is one additional URL parameter: zfact: the two class boundaries were calculated as

  • zbot = (mean - (zfact * standard deviation)  
  • ztop = (mean + (zfact * standard deviation) 

The legend is a first attempt, there is no solution for cases with zbot < zmin or ztop > zmax. In a more elaborated version there will be a bipolar color scheme (using a parameter zmed).

Here the test: