text: /*global require module */
  
  var _ = require('lodash')
  var skipto = 15
  function process_doc(doc,next){
      var data = JSON.parse(doc)
      // data.data
      var l = {}
      _.each(data.features[0].properties.data,function(row){
          // last entries in the row are the detectors used in that
          // month's solution
          var detectors = row.slice(skipto)
          _.each(detectors,function(d){
              l[d]=1 // use the hash to keep unique detectors
          });
      });
      next(null,_.keys(l))
  }
  
  module.exports=process_doc