How to Create a Spline Chart

What is a Spline Chart

Splines are smooth curve lines, using internal interpolation to avoid corners. Spline charts look great, but be aware they are not the best at precision: it’s harder to see the points the line passes through, without markers.

Spline charts can be single and multi-series, grouped or split when more then one series, single or multi-color, with a dash style, broken on missing points, with an alternative 3D view.

Steps to Create a Spline 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 Line Charts – Line chart.
3. Select eventually a Label, for legend items and X axis labels.
4. Select all line series from the toolbar and change their drawing style to Spline.
5. Multi-series charts can be split into multiple separate single-series charts.

Spline Chart Demo Queries

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. Specific Spline demo queries are 3D Spline Chart and MultiColor Spline with Category Chart.

Or build your Spline chart from scratch, as shown here. Most simple Spline chart has just one data column, with a horizontal axis automatically generated.

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.

Customize your Spline Chart

1. Make your spline chart multi-color, with a different color for each segment.
2. Show data labels as lollipops, inside some custom diamond markers.
3. Change the dash style to interrupted lines.
4. Add a data column as Label., and show staggered X axis labels.
5. Set another column as Category, to group multiple segments with the same color.
6. Click on some legend items to hide segments within that Category.
7. You may change a line drawing style to straight, spline, step or jump line.

Conclusion

• Creating Spline charts in Data Xtractor or Visual Xtractor is fast and trivial: select one or more numeric columns as Line, and one column as Label if you wish.
• Select series from the toolbar and change their drawing style to Curve Line (Spline).
• 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.