double value;
                    if (dataset instanceof IntervalXYDataset) {
                        IntervalXYDataset intervalXYData
                            = (IntervalXYDataset) dataset;
                        value = intervalXYData.getStartYValue(series, item);
                    }
                    else if (dataset instanceof OHLCDataset) {
                        OHLCDataset highLowData = (OHLCDataset) dataset;
                        value = highLowData.getLowValue(series, item);
                    }
                    else {
                        value = dataset.getYValue(series, item);
                    }
                    if (!Double.isNaN(value)) {
                        minimum = Math.min(minimum, value);