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Graph display

Display data in an XY line graph, showing one or more measurements versus time or another measurement. Modify how the data appears and analyze the data using multiple tools.

Overview

  1. Scale the graph

    • Scale to Fit

      Automatically scale the axes to make all data visible in the graph.

    • Scaling Behavior

      Select how the plot area scales while recording data:

      • Scale Both Axes

        Keep data visible in both axes when data moves out of the current range.

      • Scroll x-axis, Scale y-axis

        Keep data visible in the y-axis and a constant range on the x-axis. The x-axis scrolls over time, showing the most recent data.

      • Scroll x-axis, do not scale y-axis

        Show a constant range on the x and y axes. The x-axis scrolls over time, showing the most recent data.

  2. Select runs and data points

    • Data Selector

      Change the visibility of individual data runs without deleting the data.

    • Data Highlighter

      Click to activate the highlighter tool to highlight a range of data to analyze. If more than one run is on the plot, select a run to analyze by clicking the run in the legend before clicking the highlighter tool.

  3. Analyze multiple data points

    • Statistics

      Show the minimum, maximum, mean, and standard deviation of a range of data. Display the statistics visually on the graph or in a tabular format.

    • Area Tool

      Find the area under a curve.

    • Curve Fit Tool

      Fit a curve to data and get the curve fit parameters.

  4. Analyze a single data point

  5. Smoothing

    Smooth out noisy data. Click the Smoothing menu and drag the slider to adjust the amount of smoothing applied to the data.

  6. Prediction Tool

    Before collecting data, draw a prediction of the results directly on the graph.

  7. Edit data collection

    • Exclude Data

      Use to exclude, but not permanently delete, data points from analysis. Highlight the data you want to exclude, then click the tool to remove the data.

    • Delete Data

      Use to permanently delete data from a run without having to delete the entire run. Highlight the data you want to delete, then click the tool to remove the data.

  8. Display multiple measurements

    • Add y-axis

      Display multiple measurements on the same plot area by adding additional y-axes to a line graph.

    • Add Plot Area

      Display an additional measurement in a line graph on separate plot area located below the current plot area.

    • Remove

      Use to remove a y-axis or plot area from a graph display. Click the axis or plot area you want to remove, then click the Remove button.

    • Rearrange

      Use to rearrange y-axes or plot areas in the graph display. Click the tool, then click and drag the axes and plot areas as desired.

  9. Display tools

    • Pin Toolbar

      Click to prevent the toolbar from hiding automatically.

    • Properties

      Click to access the display properties.

    • Show or Hide Tools

      Click to show or hide specific tools from the toolbar.

  10. Select a measurement

    • Click the measurement to display:
    • Click the unit to select a different unit for the current measurement.
  11. Axis options
    • Drag to scale each axis individually. You can also use a mouse scroll wheel when the cursor hovers over the axis.
    • Click to show the axis tools.
    • Double click the maximum or minimum axis value to set each to a specific value.
    • Right-click to change the axis properties and lock the scale.
  12. Plot area options

  13. Legend

    Select a run to analyze by clicking the run in the legend. Right-click the run symbol to change the run color and other data set properties.

  14. Enter a graph title

    Click, then enter a custom title for the display.

Change the scale and range

Change the scale of a line graph to zoom in on a range of data, or to view an entire run of data.

Automatically scale to view all data

Do one of the following:

  • In the graph toolbar, click Scale to Fit .

    Tip

    Click the menu and select Auto scale from zero to keep the graph origin visible.

  • Click the horizontal axis, then click Scale to Fit .

Scale each axis individually

  • Drag the axis away from the origin to zoom in.
  • Drag the axis toward the origin to zoom out.
  • Hover the cursor over the axis and scroll the mouse wheel to zoom in or out.

Tip

To prevent an axis from scaling, right-click the axis and select Lock Axis Scale in the menu. This is useful when displaying multiple y-axes.

Change the range of the graph but not the scale

You can change the range of data displayed in a graph without changing the scale by moving the graph. To move the graph, click and drag the graph to the desired range.

Tip

When viewing a graph with more than one y-axis, you may want to prevent the range from changing. To do this, right-click the axis then select Lock Axis Panning from the menu.

Zoom in on a range of data

Note

If displaying multiple runs of data, first select a run in the legend.

  1. Go to the graph toolbar and click Data Highlighter to make the highlighter visible.
  2. Drag the highlighter over the data you want to analyze. Use the handles on the highlighter to resize the highlighter.
  3. In the graph toolbar, click Scale to Fit .
  4. Optional: To remove the highlighter, click on it, then click Remove .

Show or hide runs

Change the visibility of individual data runs without deleting the data.

Note

This section explains how to hide data runs from display. To delete data runs, see Delete data runs.

View one run

Go to the graph toolbar and click the Data Selector menu . Select the run you want to display from the menu.

View multiple runs

  1. Click Data Selector to activate the multiple-run view.
  2. Click the Data Selector menu , then select the runs you want to display.

Display data statistics

Use the statistics tool to find the minimum, maximum, mean, and standard deviation of a range of data. Display the statistics visually on the graph or in a tabular format.

Note

If displaying multiple runs of data, first select a run in the legend.

  1. Go to the graph toolbar and click Data Highlighter to make the highlighter visible.
  2. Drag the highlighter over the data you want to analyze. Use the handles on the highlighter to resize the highlighter.
  3. Click Statistics , then select the statistics you want to display.

The graph displays the selected statistics visually by default. You can also display all statistics in a table by clicking a statistic value, then clicking Tabular Statistics . To return to the visual statistics format, click the table, then click Visual Statistics .

Find the area under a curve

Use the area tool to find the area under a curve.

Note

If displaying multiple runs of data, first select a run in the legend.

  1. Go to the graph toolbar and click Data Highlighter to make the highlighter visible.
  2. Drag the highlighter over the data you want to analyze. Use the handles on the highlighter to resize the highlighter.
  3. In the graph toolbar, click the Area tool.

The shaded area under the curve indicates the measured area. An information box appears displaying the magnitude of the area with units.

Tip

To change the number of digits displayed, right-click the information box, then select Tool Properties. Adjust the numerical format as desired.

Fit a curve to data

Use the curve fit tool to fit a curve to data and obtain values about the trend line parameters. Use the Curve Fit Editor to make adjustments to the curve fit parameters.

Apply a curve fit

Note

If displaying multiple runs of data, first select a run in the legend.

  1. Go to the graph toolbar and click Data Highlighter to make the highlighter visible.
  2. Drag the highlighter over the data you want to analyze. Use the handles on the highlighter to resize the highlighter.
  3. Click Curve Fit Tool, then select the desired curve fit from the menu.

Tip

If the curve fit fails, use the curve fit editor to suggest possible values for the curve fit parameters.

A curve appears over the data with an information box. The information box includes values about the trend line parameters. Also included are the mean square error, MSE, and the root mean square error, RMSE, which provide information on how well the curve fits the data.

Display multiple curve fits

Capstone automatically displays additional curve fits if you add additional data highlighters to the graph. This can be useful if you want to analyze two different sections of a data run. In the following example, two linear fits are used to determine the equivalence point in a reaction by viewing where the two lines intersect.

Edit the curve fit parameters

A curve fit may fail for data that has a complex trend. For these cases, you need to use the Curve Fit Editor to suggest approximate values for some of the curve fit parameters. You can also use the Curve Fit Editor to make precise adjustments to successful curve fits.

  1. Click the curve fit information box, then click Curve Fit Editor .
  2. In the Curve Fit Editor panel, enter an Initial Guess for at least one of the curve fit parameters.

  3. Click Update Fit.

    Tip

    If the fit fails, click Lock to prevent a parameter from automatically changing, then click Update Fit again.

Edit the curve fit properties

Use the Curve Fit Properties to adjust properties such as the number of significant digits used, visibility of information displayed, and how the information appears.

  1. Click the curve fit information box, then click Properties .
  2. Navigate through the menus in the Properties window, then make adjustments to the desired properties.
  3. Click OK to apply the properties.

Determine the coordinates of data points

Determine the coordinates of a single data point or compare data point coordinates from multiple measurements and runs.

Coordinates of a single point

Use the coordinates tool to determine the coordinates of a single data point.

  1. Click the data point you want to analyze, then click the Coordinates tool.
  2. Place the tool on a different data point by clicking and dragging the tool, or by clicking Previous Data Point or Next Data Point .

To remove the tool from the screen, click the coordinates tool, then click Remove .

Tip

Click the Delta tool to determine the difference between two data points.

Compare coordinates of multiple points

Use the multi-coordinates tool to compare coordinates across multiple runs or measurements.

  1. Click Coordinates in the graph toolbar, then select Add Multi-coordinates Tool.
  2. Place the tool on a different data point by clicking and dragging the tool, or by clicking Previous Data Point or Next Data Point .

Adjust the snap-to pixel distance

Use Tool Properties to adjust the range at which the coordinates tool snaps to the nearest data point.

  1. Right-click the coordinates tool on the graph display (either on the display box or on the tool itself) and select Tool Properties, as shown below.

    Accessing Tool Properties

  2. From the Tool Properties menu, open the Coordinates submenu.

  3. Enter a new value in the box next to Snap-to Pixel Distance. This property controls how many pixels away the coordinate has to be from the nearest data point before automatically relocating to that point.

    Tool Properties menu

  4. Click OK.

Find the difference between two points

The coordinates tool in a graph display includes a delta tool to determine the difference between two data points in a run of data. Activate the delta tool to display the difference between the vertical, Δy, and horizontal, Δx, coordinates.

  1. Click the point you want to analyze, then click Coordinates Tool.
  2. Click Delta to make the Delta tool visible.
  3. Place the tool on a different data point by clicking and dragging the tool, or by clicking Previous Data Point or Next Data Point .

To remove the tool, click the tool and click Delta Tool or Hide Delta Tool .

Align a run to an axis or another run

Shift a data run in a graph display by aligning a data point with an axis or a second data run.

Note

The alignment tool is only available when the x-axis measurement is Time.

Align a run to an axis

Shift a data run by aligning a data point with the y-axis, x-axis, or the origin of a graph.

  1. In the graph toolbar, click Coordinates , then select Add Alignment Tool.
  2. Drag the coordinates tool and attach it to the data point you want to shift.

  3. Click the Alignment tool, then select the type of alignment:

    A) Align to x-axis

    Shift the data point to make its y-coordinate equal to zero.

    B) Align to y-axis

    Shift the data point to make its x-coordinate equal to zero.

    C) Align to origin

    Shift the data point to make its x- and y-coordinate equal to zero.

Align two data runs

Shift a data run along the Time axis to align it with a second data run.

  1. In the graph toolbar, click Coordinates , then select Add Alignment Tool.
  2. Drag the coordinates tool and attach it to the data point where you want to align the runs.
  3. Click the Alignment tool, then select Align Runs. A second coordinates box appears.

  4. Drag the second coordinates box and attach it to the data point you want to shift.

  5. Click Align runs to align the runs.

Find the slope of the tangent to a curve

The slope tool provides the slope of a line tangent to a curve at a single point.

Tip

See linear fit to find the slope of a range of data.

  1. Click the data point you want to analyze, then click Slope .
  2. Place the tool on a different data point by clicking and dragging the tool, or by clicking Previous Data Point or Next Data Point .

To remove the tool from the screen, click on the tool and click Remove .

Label a data point in a line graph

Use the annotation tool to label a data point in a graph with a brief note.

Add an Annotation to a Data Point

  1. Click the data point where you want to leave a note, then click Annotation .

  2. Click the annotation box, then use your keyboard to type a note.

    Tip

    To enter superscripts, subscripts, or special characters, right-click the annotation box and select the character you want to enter from the menu.

To remove the tool from the screen, click on the tool and click Remove .

Modify the Appearance of the Annotation

  1. Right-click the annotation box, then go to Text Annotation Tool and select Text Annotation Tool Properties.
  2. Modify the annotation tool properties as desired.
  3. Click OK to exit the Properties window.

Draw a prediction on a line graph

Before collecting data, draw a prediction of the results directly on the graph.

Draw a prediction containing curves

  1. Go to the graph toolbar, then click Prediction .
  2. Select Create Free Form Prediction from the menu.
  3. Click and drag on the screen to draw your prediction. Release the mouse button when finished.

Draw a prediction as a series of lines

  1. Go to the graph toolbar, then click Prediction .
  2. Select Create Point-by-Point Prediction from the menu.
  3. Click on the graph to mark your first point, then click at another location to mark your second point. The two points connect with a line. Repeat to draw additional lines.
  4. Click Done at the top of the graph when finished.

Delete a prediction

  1. In the Tools palette, click Data Summary .
  2. Under Sensor Data Summary, select the prediction you want to delete.
  3. Click Remove next to the prediction you want to delete.
  4. Click Yes to confirm deletion.

Add or remove an additional y-axis

Display multiple measurements on the same plot area by adding additional y-axes to a line graph.

Tip

If you want to add another plot area below the current plot area, see Add a Plot Area.

Add an axis

  1. Add a y-axis using one of the following methods:
    • In the graph toolbar, click Add y-axis .
    • Click the y-axis of the current graph, then click Add y-axis .
  2. On the new axis, click Select Measurement, then select a measurement from the list.

Remove an axis

Click the axis you want to remove, then click Remove .

Add or remove a plot area

Display an additional measurement in a line graph on separate plot area located below the current plot area.

Tip

If you want to add a second y-axis to the graph on the same plot area, see Add a y-axis.

  1. Add a plot area using one of the following methods:
    • In the graph toolbar, click Add Plot Area .
    • Click the horizontal axis, then click Add Plot Area .
  2. In the new plot area, click Select Measurement, then select a measurement from the list.

To remove a plot area, click the plot area you want to remove, then go to the graph toolbar and click Remove . You can also press the Delete button on your keyboard.

Display a calculation of a measurement

Use the QuickCalc feature to quickly display a calculation of a measurement on a Graph display.

  1. Set up a measurement on a Graph display.
  2. Click the measurement, then navigate to QuickCalc.
  3. Select a calculation from the list.

The resultant calculation displays on the graph. The calculation is also displayed in the measurement name and unit on the axis.

Tip

Use the Calculator to create more complex calculations.

Hide data points and connecting lines

Change the visibility of data points, symbols, and lines connecting data points in a line graph.

To quickly change the visibility of data points, run symbols, and connecting lines, right-click a data point in a run and select or deselect the options that appear in the menu.

For more detailed control over the data appearance such as data point size and connecting line width, right-click a data point and select Run Properties .

Add error bars

Add error bars to one or more runs in a Graph display.

Display error bars for a run

Make error bars visible for an individual run.

  1. In the Graph display, right-click a data point in the run you want to add error bars to. Select Run Properties from the list of options.

    Access Run Properties

  2. From the Run Properties menu, select Data Appearance, then scroll down to the error bar settings.

    Error Bar Properties

  3. Click the check box next to Show Vertical Error Bars or Show Horizontal Error Bars to add that respective type of error bar to the run.

See Error bar types for information on adjusting the length of displayed error bars.

Display error bars for multiple runs

Make error bars visible for multiple selected runs.

  1. Use the Data Selection tool to make all desired runs visible.
  2. Make all visible runs active by highlighting them in the legend.
  3. From the graph toolbar, click Properties to open the Properties window.

  4. Open the Data Appearance submenu, then scroll down to the error bar settings.

    Error Bar Properties

  5. Click the check box next to Show Vertical Error Bars or Show Horizontal Error Bars to add that respective type of error bar to all selected runs.

See Error bar types for information on adjusting the length of displayed error bars.

Error bar types

Capstone includes four options for setting the length of the error bars on a run of data:

  • Default Error: Set the length of all error bars on the run to the same default value.
  • Percent Of Value: Set the length of each individual error bar to a fixed, user-entered percentage of the corresponding data point's value on the x-axis (horizontal error bars) or y-axis (vertical error bars).
  • Fixed Range: Set the length of all error bars on the run to the same user-entered value.
  • Measurement: Set the length of each individual error bar to the value of the corresponding data point on a separate run of data. For example, the first data point of the run has its error bar's length set to the first value in the selected measurement; the second data point has its error bar set to the second value in the measurement; and so on.

For each of the four options, the heights of the error bar above and below the data point can be set to different values.

Set default error bars

Set the default error bar type and lengths for a measurement.

  1. Select Data Summary in the Tools palette.

  2. Click the name of the measurement you wish to adjust the default error bars for, then click the gear icon which appears next to the name to open the Properties menu for that measurement.

    Measurement Properties

  3. Open the Errors submenu to access the error bar properties.

The error bar properties allow you to adjust:

  • Which error bar type is selected by default.
  • The value of the Default Error option.
  • The default values of the Percent Of Value and Fixed Range options.
  • The default measurement selection for the Measurement option.

Once the properties are adjusted using this tool, all new runs (or all existing runs that have not yet had error bars added) will have these settings applied by default when their error bars are enabled.

Note

If you have already set individual Percent Of Value error bars for a run or set of runs, you will need to readjust those runs manually to match the global default error bars, since existing error bars will not be adjusted to match the new default percentage.

Enable error bars by default

Tell Capstone to automatically display error bars for all measurements.

  1. Open File > Preferences.
  2. From the Preferences menu, open the Graph Properties submenu.

  3. Click Show Vertical Error Bars or Show Horizontal Error Bars to add the corresponding type of error bars to all runs in all graph displays. To remove this preference, simply uncheck the box.