# 8.5.2.1.8 The Reference Lines Tab

To identify a specific value or range, you can add multiple reference lines at a constant or computed value on the axis and fill the area between paired reference lines .

 Starting with Origin 2017, you can use the Layer list to switch between layers in a multi-layer graph.

## Reference Lines at Value

To locate the reference lines, you can enter space-separated position values in this text box or select a reference column(by clicking the Select Column interactive button beside this text box) from worksheet.

## Alternate Fill

Alternate Fill

Fill the area between every odd number reference line and its next even number reference line, such as RLine 1 ~ RLine 2, RLine 3 ~ RLine 4.

Alternate Fill Include Axis Begin and Axis End

Do Alternate Fill including Axis Begin and Axis End. The filling order is Axis Begin to RLine 1. Axis End will be the last fill to if the custom line number is even.

You can refer to this tutorial to learn how this option works.

## Display Box for Reference Lines

List all reference lines. The reference lines Axis Begin and Axis End will listed at top of this table by default.

### At Axis Value

Show the position of added reference lines.

 You can display reference lines behind or in front of your data points. See Data Drawing Options.

### Line

Specify whether to show the reference line at current axis value.

### Fill to

Select a reference line from the drop-down list which current reference line should be filled to. If you've selected any Alternate Fill check box above, this column will show the pairing lines and be not editable.

### Label

Specify whether to show label for the reference line.

### Label Text

Specify what is to be shown as label for each reference line.

• The default, <value as entered>, displays the position value as label for the current reference line.
• Select <auto> to follow the tick label format settings of the Tick Labels tab of the Axis dialog (Type, Display, Set Decimal Places, Decimal Number).
• You can also type in a custom string using the form $(v, Formats) where v is the position value and Formats uses the syntax described under Origin Formats. There are two special cases: $(v,D99) // v = Julian-Day value in the form "MM/dd/yyyy hh:mm:ss" when Tick Label Type=Date
$(v,T99) // v = Julian-Day value in the form "DDD:hh:mm:ss" when Tick Label Type=Time By default, the label object has the following properties: • A label is positioned at the top of the reference line but can display in the middle or at the bottom. • A Name that displays on the Programming tab of the Properties dialog box. This name is RL(X/Y)#, where "X" or "Y" identifies the axis and "#" is the order in which the line appears in the Reference Lines list (e.g. RLX3 would be the third reference line in the list associated with the X axis). • Attached to the graph by Layer and Scales. • A Link to (%,$) Substitution Level of 1, which means the object is dynamically linked to value of variable v.

### Label Location

Specify the position of the labels. For Vertical lines, possible positions are top/middle/bottom of the reference lines; For Horizontal lines, possible positions are left/middle/right of the reference lines.

## Button

There are three buttons under the display box:

 Insert Insert a new reference line before the one you selected in display box. Delete one or more reference lines that are selected in the display box. (i.e. the reference lines other than the Axis Begin and Axis End ones). To select multiple lines, hold down Ctrl key and click on the reference line entries one by one. Open the Reference Lines dialog for further style customization of the reference lines.
 Note: To enable Insert and Delete buttons, you should clear Reference Lines at Value at first.

## Details dialog for Reference Lines

This dialog can be opened by clicking the Details... button in the Reference Lines tab of Axis dialog. It is used to customize formats and styles of all reference lines.

 When this dialog is open, the main Axis dialog will be hidden. And you can click Apply button to apply the change in this dialog only, without coming back to the main Axis dialog. When click OK button to save the setting and close this dailog / click Cancel button to close this dialog, the main dialog will show again.

### Value Type

Select the value type that the reference line specifies. It only appears for custom reference lines(excluding Axis Begin and Axis End).

 Value Add a reference line at a constant value on the axis. Add a reference line generated by a formula of curve or at a computed value calculated by an expression. Add a reference line at a statistical value.

### At Axis Value

Specified the position at which the reference line should be added. It only appears for custom reference lines(excluding Axis Begin and Axis End).

For Value Enter a constant value on the axis.
For Expression Enter a LabTalk expression. Origin offers many built-in functions for building the expression. You can click the fly-out button next to the edit box, then select a function and insert it in the edit box.

Note: The letters x and y are the reserved variables that refer to the current x axis and y axis, respectively. If you want to add a line y = x + 1 to the graph, you can directly input “x + 1” in At Axis Value edit box.

For Statistics Enter a statistical function which is used to calculate the statistics info of plot. Also, Origin offers built-in statistical functions. You can use one of them directly by clicking the fly-out button next to the edit box.

Note:

1. In order to get the statistics info of the plot, it is very common to nest the function plotdata() within a statistical function. For example,
Min(plotdata(1,Y)); //The minimun value of the first plot’s Y data
2. In trellis plot, we can get the statistics info of every panel by nesting plotdata(index, designation, h,v), for example,
Min(plotdata(1, Y, h, v)); //The minimum value of the first plot’s Y data for every panel
Likewise, we can get the statistics info of all horizontal panels for every panel row by plotdata(index, designation, *,v), and the statistics info of all vertical panels for every panel column by plotdata(index, designation, h,*). Nesting plotdata(index, designation) in a statistical function is to get the statistics info for all data of this trellis plot without considering panels, for example,
Min(plotdata(1, Y)); //The minimum value of all the first plot’s Y data in this trellis plot
3. Sometimes, we will mix up the panels in a different order after wrapping panels, exchanging XY, reversing axis. To help to figure out the real panel index, Origin will show the panel index labels on the trellis plot when you activate Reference Lines tab of Axis dialog.
 Statistical reference lines are dynamic and will recalculate and redraw with changes to supporting data, as for instance, when you add a data filter; you change data range; or when you hide or show data plots with the Object Manager.
 Note: Apart from the formula including the variable x and y, we should specify a single value in At Axis Value edit box. For dataset, only the first element will be taken account into. For example, the reference line will only show at x/y = sin(1) if we enter “sin(data(1,32))” in At Axis Value edit box.

### Show on Panel

Specify on which panel the reference line is shown. It is only available in trellis plot. Use the commas to divide the panel index.

### Line

The Show check box is consistent with the Line check box in the Display table. You can use it to show or hide the reference line.

Unchecking Auto Format check box to customize the Color, Style and Thickness of current reference line.

### Pattern

Customize Fill Pattern between paired reference lines.

Select the fill target lines from Fill To drop-down list. It is consistent with the Fill To option in the Display table. If any Alternate Fill is applied, this drop-down list turns gray.

Customize the fill color and color transparency using the Color and Transparency options.

 Note: You can easily copy the style of one reference line to others by Copy Format and Paste Format in this dialog. Right click on a reference line in the left panel Reference Lines at and select Copy Format, and then select the target reference line(s) and right click to Paste Format. What's more, you can select Duplicate in the context menu to create a new reference line with the same style.

### Label

Customize the label for reference line.

 Show Specify whether to show a label for the reference line. Specify what is to be shown as a label for the reference line. We have talked a lot in aforementioned section. Specify which label form is to be shown for the reference line. It only appears for statistics reference lines. Value: To show the statistics value as a label. Quantity: To show the quantity as a label. Both: To show the statistics value and the quantity as a label in a format of quantity = statistics value. Custom: To show a customized text label. Specify which name to be shown on the label to identify the plot. Specify the position of the labels.