X Axis Vs. Category Axis
Possible Usage Scenarios
There are different types of X axes. While the Y axis is a Value type axis, the X axis can be a Category type axis or a Value type axis. Using a Value axis, the data is treated as continuously varying numerical data, and the marker is placed at a point along the axis which varies according to its numerical value. Using a Category axis, the data is treated as a sequence of non-numerical text labels, and the marker is placed at a point along the axis according to its position in the sequence. The sample below illustrates the difference between Value and Category Axes. Our sample data is shown in the sample Table file below. The first column contains our X axis data, which can be treated as Categories or as Values. Note that the numbers are not equally spaced, nor do they even appear in numerical order.
Handle X and Category axis like Microsoft Excel
We will display this data on two types of chart,the first chart is XY (Scatter) chart X as Value Axis, the second chart is line chart X as Category Axis.
Sample Code
// Create an instance of Workbook | |
Workbook workbook = new Workbook(); | |
// Access the first worksheet. | |
Worksheet worksheet = workbook.Worksheets[0]; | |
// Put the sample values used in charts | |
worksheet.Cells["A2"].PutValue(1); | |
worksheet.Cells["A3"].PutValue(3); | |
worksheet.Cells["A4"].PutValue(2.5); | |
worksheet.Cells["A5"].PutValue(3.5); | |
worksheet.Cells["B1"].PutValue("Cats"); | |
worksheet.Cells["C1"].PutValue("Dogs"); | |
worksheet.Cells["D1"].PutValue("Fishes"); | |
worksheet.Cells["B2"].PutValue(7); | |
worksheet.Cells["B3"].PutValue(6); | |
worksheet.Cells["B4"].PutValue(5); | |
worksheet.Cells["B5"].PutValue(4); | |
worksheet.Cells["C2"].PutValue(7); | |
worksheet.Cells["C3"].PutValue(5); | |
worksheet.Cells["C4"].PutValue(4); | |
worksheet.Cells["C5"].PutValue(3); | |
worksheet.Cells["D2"].PutValue(8); | |
worksheet.Cells["D3"].PutValue(7); | |
worksheet.Cells["D4"].PutValue(3); | |
worksheet.Cells["D5"].PutValue(2); | |
//Create Line Chart: X as Category Axis | |
int pieIdx = worksheet.Charts.Add(ChartType.LineWithDataMarkers, 6, 15, 20, 21); | |
// Retrieve the Chart object | |
Chart chart = worksheet.Charts[pieIdx]; | |
// Add Series | |
chart.NSeries.Add("B2:D5", true); | |
// Set the category data | |
chart.NSeries.CategoryData = "=Sheet1!$A$2:$A$5"; | |
// Set the first series mame | |
chart.NSeries[0].Name = "Cats"; | |
// Set the second series mame | |
chart.NSeries[1].Name = "Dogs"; | |
// Set the third series mame | |
chart.NSeries[2].Name = "Fishes"; | |
// Set the Legend at the bottom of the chart area | |
chart.Legend.Position = LegendPositionType.Bottom; | |
// Fill the PlotArea area with nothing | |
chart.PlotArea.Area.FillFormat.FillType = FillType.None; | |
// Create XY (Scatter) Chart: X as Value Axis | |
pieIdx = worksheet.Charts.Add(ChartType.ScatterConnectedByLinesWithDataMarker, 6, 6, 20, 12); | |
// Retrieve the Chart object | |
chart = worksheet.Charts[pieIdx]; | |
// Add Series | |
chart.NSeries.Add("B2:D5", true); | |
// Set X values for series | |
chart.NSeries[0].XValues = "{1,3,2.5,3.5}"; | |
chart.NSeries[1].XValues = "{1,3,2.5,3.5}"; | |
chart.NSeries[2].XValues = "{1,3,2.5,3.5}"; | |
// Set the first series mame | |
chart.NSeries[0].Name = "Cats"; | |
// Set the second series mame | |
chart.NSeries[1].Name = "Dogs"; | |
// Set the third series mame | |
chart.NSeries[2].Name = "Fishes"; | |
// Set the Legend at the bottom of the chart area | |
chart.Legend.Position = LegendPositionType.Bottom; | |
// Fill the PlotArea area with nothing | |
chart.PlotArea.Area.FillFormat.FillType = FillType.None; | |
// Save the Excel file | |
workbook.Save("XAxis.xlsx"); |