code: function (position, datum) {
                      var val;
                      if (series.interpolation === "step" && series[position]._hasCategories()) {
                          val = dimple._helpers[position](datum, chart, series) + (position === "y" ? dimple._helpers.height(datum, chart, series) : 0);
                          if (series[position].categoryFields.length < 2) {
                              val += (position === "y" ? 1 : -1) * dimple._helpers[position + "Gap"](chart, series);
                          }
                      } 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.  UPDATE: Turns out it isn't, see Issue #79.  points > pixels
                      // causes multiple points to fall on the same co-ordinate which results in drawing problems.
                      return parseFloat(val);
                  }
docs: Get the position data