Average line in time series with iReport

Question

how can i draw the average line in a time series?

Answer 1

Solutions

There are a few ways to do this:

• Perform in-line trend analysis and write a chart customizer to perform the calculations. See also:
  • Trend analysis using iterative value increments
  • Best fit curve for trend line
• Use an integrated statistical package with your database to perform a statistical analysis. See also:
  • Non-linear regression models in PostgreSQL using R
• Use a third-party tool to perform the analysis. See:
  • http://www.revolutionanalytics.com/

In-line Analysis

The disadvantage to performing the analysis in-line is that JasperReports plots a single value at a time. Any customizer you write will have to calculate the trend based on the past data points, rather than an analysis on all the data points at the end. This will cause a slight skew to the data line.

Integrated Stats Package

The disadvantage to using a statistics package is that you would have to find a way to integrate it with your database. (You would also have to learn the corresponding statistical functions to perform the analysis.)

Third-party Tool

The disadvantage here is that you might have to pay for the product, or support. The integration is likely the easiest.

Recommended Solution

If you have a PostgreSQL database, I would recommend installing PL/R. Use R to perform the aggregate data analysis and then send the result back to JasperReports for the time series chart.

What you are asking to do can be quite involved.