How to Create a Spline Area Chart

What is a Spline Area Chart

A Spline Area is an Area Chart delimited by one or two Curve (Spline) Lines.

We may display the following types of Spline Area charts (only the first two types are described here):

1. Spline Area Chart – Cartesian single-series area delimited by a curve line.
2. Grouped Spline Area Chart – Cartesian multi-series areas with curve lines.
3. Stacked Spline Area Chart – Cartesian multi-series spline areas on top of each other.
4. Range Spline Area Chart – Cartesian areas delimited by two curve lines each.

Steps to Create a Spline Area Chart

Start Visual Xtractor or Data Xtractor. Connect to a database. Create or design a SQL query. Run the query and check the results.

1. Display and enable the Chart query builder.
2. Select one or more numeric columns with the Area Charts – Area chart.
3. Change their line drawing style to a Curve (Spline) Line.
4. Select eventually a Label, for legend items and X axis labels.
5. Multi-series charts can be split into multiple separate single-series charts.

Simple Spline Area Charts

Look for ready-to-use generated chart queries under the Queries > Demo Queries > Charts folder. Click on the “add demo queries” command link, to make sure they’re all there.

Or build your Spline Area chart from scratch, as shown here. Most simple Spline Area chart has just one data column, with a horizontal axis automatically generated. You change its line style to a Curve (Spline) Line with a toolbar drop-down button.

Generated demo queries must work for any database, with no restriction. They use constant values generated on-the-fly and your database SQL engine, but do not depend on data from your tables, and never alter your database in any way.

Grouped Spline Area Charts

More than one Spline Area selection create a Grouped Spline Area Chart. All areas start from zero, so they may get partially or fully covered by other areas. That’s why a semi-transparent fill is recommended.

Individual area charts may be selected one by one from the toolbar and have the drawing style, line style or markers changed. Or change them all together, with the default “(all)” series selection.

Customize your Spline Area Chart

1. Make your area chart multi-color, with a different color for each segment.
2. Show data labels, with custom X markers.
3. Show X axis labels as staggered.
4. Click on some legend items to hide individual segments.
5. You may change the area’s line drawing style to straight, spline, or a step line.

Conclusion

• Creating Spline Area Charts in Data Xtractor or Visual Xtractor is fast and trivial: select one or more numeric columns as Area, and change their line style to Curve (Spline) Line.
• All builtin powerful features of these chart type are common to most other charts: filtering series through the legend items, interactivity, monochrome or grayscale colors, rich axis and data label selections etc.
• Switch to another builtin chart theme, or customize your own, for any possible color or other styles.