code: function (position, datum) {
                      var val;
                      if (series.interpolation === "step" && series[position]._hasCategories()) {
                          series.barGap = 0;
                          series.clusterBarGap = 0;
                          val = dimple._helpers[position](datum, chart, series) + (position === "y" ? dimple._helpers.height(datum, chart, series) : 0);
                      } else {
                          val = dimple._helpers["c" + position](datum, chart, series);
                      }
                      // Remove long decimals from the coordinates as this fills the dom up with noise and makes matching below less likely to work.  It
                      // shouldn't really matter but positioning to < 0.1 pixel is pretty pointless anyway.
                      return parseFloat(val.toFixed(1));
                  }
docs: Get the position data