code: function(fc, z, numBreaks, colors, style){
      var vals = _.chain(fc.features)
        .pluck('properties')
        .pluck(z)
        .value()
  
      var min = ss.min(vals)
      var max = ss.max(vals)
      var interval = (max - min) / numBreaks
      var breaks = [0]
      var currentBreak = 0
      for(var i=0;i<=numBreaks;i++){
        currentBreak += interval
        breaks.push(currentBreak)
      }
      var normals = normalize(breaks.length)
      fc = colorize(fc, z, colors, breaks, normals)
      fc = setLegend(fc, z, colors, breaks, normals)
      fc = applyStyle(fc, style)
      return fc
    }
docs: EQUAL INTERVAL