anchor.diff:          cartocss.push @_generateCartocss(
             table: [POLYGONS_TABLE, POINTS_TABLE]
             attrName: 'wdpaid'
  -          attrVal: config.wdpaId
  +          attrVal: config.wdpaId,
  +          polygonCompOp: 'src-over'
           )
   
         {
  
positive.code:         opacity: 0.7
          lineWidth: 0.05
          lineColor: '2B3146'
          polygonFill: '2B3146'
        }, args)
  
        """
  
negative.code:           line-width:#{args.lineWidth};
            polygon-fill:##{args.polygonFill};
            polygon-opacity:#{args.opacity};
            polygon-comp-op:#{args.polygonCompOp};
          }
        """
  
  