# 9.3.7.2 The (Plot Details) Line Tab

Line customization is possible for a wide range of plot types. Consequently, the actual suite of controls available on the Line tab varies and is plot-type dependent. This reference topic reviews all of the possible controls on this tab. Some controls will not be available for some plot types.

 Line tab for general 2D Line/ Line+Symbol graph Line tab for 3D Scatter/Trajectory/Vector graph

## Connect

Select the desired line connection from this drop-down list.

No Line The data points are not connected. A straight line is displayed between data points. The connection display alternates between Straight and No Line. The connection display alternates between Straight for three points, No Line, Straight for three points, etc. For a pair of data sets with coordinates $\left( X[i],Y[i]\right),i=1,2,...n$ Origin makes a smooth curve using a cubic B-spline connection. The B-spline curve can be described by parametric equations. Around point $\left( X[i],Y[i]\right)$ it takes the form: $X_i[t]=\frac 16\left\{ \left( -t^3+3t^2-3t+1\right) X\left[ i-1\right] +(3t^3-6t^2+3t)X\left[ i\right] +\left( -3t^3+3t^2\right) X\left[ i+1\right] +t^3X\left[ i+2\right] \right\}$ and $Y_i[t]=\frac 16\left\{ \left( -t^3+3t^2-3t+1\right) Y\left[ i-1\right] +(3t^3-6t^2+3t)Y\left[ i\right] +\left( -3t^3+3t^2\right) Y\left[ i+1\right] +t^3Y\left[ i+2\right] \right\}$ where $2\leq i\leq n-2$. The coordinates are calculated around each point, letting t range from 0 to 1. This cubic B-spline curve is continuous up to a second order derivative. Unlike spline curves which pass through the original data points $\left( X[i],Y[i]\right)$, the B-spline curve winds around the original data points without passing through them. (Origin duplicates the first and last data points so the curve passes through them.) This option generates a cubic spline connection. To use the connection, the X values must be discrete and increasing. Furthermore, the number of data points cannot exceed 900 (if the size of the data set exceeds this number, the operation will fail). Since curvature information is held in memory, the spline resolution remains the same regardless of page magnification. The SplineStep variable in the ORIGIN.INI file controls the spline calculation increment. It is expressed in units of 0.1 points. This option generates a right angle connection. The initial line is horizontal. This option generates a right angle connection. The initial line is vertical. This option generates a right angle connection. Each point is in the middle of the horizontal run. This option generates a right angle connection. Each point is in the middle of the vertical run. This option generates a Bezier curve. The Bezier curve is very similar to the B-spline curve. It can be described by parametric equations around four original data points: $X[t]=\left( -t^3+3t^2-3t+1\right) X\left[ 1\right] +(3t^3-6t^2+3t)X\left[ 2\right] +\left( -3t^3+3t^2\right) X\left[ 3\right] +t^3X\left[ 4\right]$ $Y[t]=\left( -t^3+3t^2-3t+1\right) Y\left[ 1\right] +(3t^3-6t^2+3t)Y\left[ 2\right] +\left( -3t^3+3t^2\right) Y\left[ 3\right] +t^3Y\left[ 4\right]$ Origin uses four consecutive data points, say $\left( X[i],Y[i]\right),i=1,2,3,4,$to construct a section of the Bezier curve, letting t range from 0 to 1. The curve always passes through the first and the fourth points, but not the second and third. The next section of the curve is constructed with $\left( X[i],Y[i]\right),i=4,5,6,7,$, and the process is repeated until all data points are included (if the total number of points is not a multiple of 4, the remaining 1-3 points are not used in the connection). The derivatives of the curve are not continuous over the whole range; but within each section (where t ranges from 0 to 1), the curve is continuous up to the second order derivative. This connection method generates a Bezier curve using the same algorithm as the Bezier method, but instead of using four consecutive data points, it uses two points from the data and two interpolated points as control points. This connection method generates an Akima Spline with the Akima Spline interpolation algorithm. The akima interpolation will not oscillate because of outliers.
 Notes: One similarity of the B-Spline and Spline connection types is that B-Spline shares Spline's requirements that X-values be discrete and increasing, and the number of points be less than 900. If the Connect is not No Line, Straight, 2 Point Segment nor 3 Point Segment (i.e. interpolation is used and it is not linear interpolation), it is then possible to generate the interpolated data directly from the data plot. To do this, right click on the data plot and choose Create Line Connect Type Data from the context menu. The Line Connect Type in the context menu will be the same as the option selected in the Connect drop-down list. When the datasets contains missing value, some connect method may not available, in order to connect the data with smooth line, you can use the Analysis:Mathematics:Interpolate/Extrapolate to create

## Connect Symbols

Specify whether connect the symbols using straight line for 3D Scatter/Trajectory/Vector graph.

## Style

Select the desired line connection from this drop-down list. For the 2D line or line+symbol graph, you can select a column from the drop-down list to set the connection line style indexed by that column. The values in the indexing column are used to designate the index of the style list. Please note that only columns in the current worksheet will be listed in the drop-down list.

 Note: You can customize the dash patterns using the Origin Dash Lines group controls on the Graph tab of the Options dialog box (Preferences: Options). At low screen resolutions or in small windows, the dashed lines may appear solid. However, a printout should draw the line correctly.

## Compound Style

Select the desired compound style of line from this drop-down list.

## Width

Type or select the desired line width in this combination box. The line width is measured in points, where 1 point=1/72 inch.

For 2D line or line+symbol graph, you can select a column from the drop-down list to map line width to that column. Please note that only columns in current worksheet will be listed in the drop-down list.

## Color

Select the desired line color from this drop-down list.

In a Line & Symbol data plot, the symbol color is set to Automatic by default, which means it matches the line color. Symbol color can be set on the Symbol tab.

 When the Color is set to Increment or Index, the line colors for each segments can be further defined in the Color List tab.

## Symbol/Line interface

This group is available only when the plot type is Line+Symbol.

### Gap to Symbol

Add a gap at the interface of the symbols and the connect line.

### Draw Line In Front/Draw Line Behind

This radio box will be available only when the Gap to Symbol check box is unchecked. You can use this radio box to specify how to draw the line for the Line+Symbol plot: draw the line in front of symbol or draw the line behind the symbol.

## Transparency

This controls how much the lines can be seen through. Move the slider or type a desired integer from 0 to 100 in the combination box. Note that 0 means the symbol is not transparent at all, and 100 means the symbol is fully transparent.

## Fill Area Under Curve

You can generate area or fill area plots directly from menu item Plot > Basic 2D: Area or Plot > Basic 2D: Fill Area, but it is also possible to customize a line or line&symbol plot to fill the area. If the Fill Area Under Curve box is selected, a drop-down list will be activated providing the options in the table below. A Preview image to the right of the Fill Area check box illustrates the area to be filled.

Additionally, when the Fill Area Under Curve check box is selected, a Pattern tab is added to Plot Details for customizing the fill area. When you opt for Fill to next data plot - Above Below Colors, two Pattern tabs are added and named as Pattern_Above and Pattern_Below, allowing for separate customization of the "above" and "below" fills.

Normal Fill the area bordered by the data plot line and the bottom X axis (assuming the axis position does not have offset) for a line or a line + symbol data plot. For a polar data plot, fills the area bordered by the data plot line and the bottom X-axis major grid lines at 0 and 180 degrees. Sidelines will be shown when this option is chosen. Fill the area between the data plot and a baseline defined by the first and last data points in the data plot. If the data plot includes missing values, Origin fills the first segment of the data plot (up to the first missing value), and then fills the second segment of the data plot up the next missing value, etc. This option is ideal if you want to fill an enclosed area determined by a data plot. Fill the area outside the data plot and the baseline defined by the first and last data points.If the data plot includes missing values, it fills the area outside of the first segment of the data plot (up to the first missing value), and then fills the area outside of the second segment of the data plot up the next missing value, etc. This option is ideal if you want to fill the region outside of an enclosed area determined by a data plot. Draw two vertical lines between the data plot line and the bottom X-axis (assuming the axis position is not offset) for a line or a line + symbol data plot. If the data plot includes missing values, use this option to fill some bars according to the missing values. The width of each bar is determined by the number of corresponding missing values. Draw two vertical lines between the data plot line and the bottom X-axis (assuming the axis position is not offset) and also a baseline for a line or a line + symbol data plot. Fill the same area as the Normal option, but not display the sidelines. If there are more than one line(or line&symbol) plot in this graph layer, this option fills the area between the selected data plot and the data plot next to it with one color, the sequences of data plots can be determined in the Layer Contents dialog. Fill to Option list: Common X Area Fill areas in common X range. Area Enclosed by End Points Fill areas enclosed by the end points of two plots. This option fills the same area as the Fill to next data plot - One Color option, but if the two data plots intersects in one or more data points other than the start or end points, the fill patterns for the areas where curve A is higher and where curve B is higher can be separately customized. Fill to Option list: Common X Area Fill areas in common X range. Area Enclosed by End Points Fill areas enclosed by the end points of two plots.

## Symbol/Line interface

This section will only be available when the plot type is set to Line + Symbol.

Select the Gap to Symbol check box to display a gap between each symbol and associated line for data plots that include both lines and symbols. To alter the size of this gap, edit the Gap to Symbol (%) box on the Graph tab of the Options dialog box (Preferences: Options).

When the Gap to Symbol check box is cleared, the Draw Line in Front and Draw Line Behind radio buttons are available, allowing you to control the display of the line going through the symbol.

To display the line as it goes through the symbol, select the Draw Line in Front radio button. Alternatively, select the Draw Line Behind radio button to hide the line.

 Note: The Draw Line in Front and Draw Line Behind radio buttons have the same visual effect on a data plot with Symbol Interior set to 'hollow': the line always displays as it passes through the symbol. To hide the line, select Open from the Interior drop-down list (with Show Construction selected) on the (Plot Details) Symbol tab. Set Fill Color to the same color as the background color of the Layer.