docs: function(geometry) {
          var units = this.displaySystemUnits[this.displaySystem];
          var unit, length;
          for(var i=0, len=units.length; i<len; ++i) {
              unit = units[i];
              length = this.getLength(geometry, unit);
              if(length > 1) {
                  break;
              }
          }
          return [length, unit];
      }