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JFree chart trending line

 
venkat xyz
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Hi all,

I have requirement like need to show the scatter plot with trend line and need to export graphs into pdf.
now my challenges are
need to show the trending line , can i use the jqplot plugin to integrate with jfreechart.
other wise i have to migrate to jqplot , wants to confirm whether we can extract the jqplots to pdf
can any one guide me , how to approach

Thanks in advance
 
Ulf Dittmer
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I'm not familiar with jqplot, but you can easily save JFreeChart charts as images, and use any number of PDF libraries to create PDFs from those.

As to trend lines, you could calculate the points that make the trend line, and ad those as an additional dataset in JFreeChart. That may be easier than to add another library to the mix.
 
Richard Tookey
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JFreeChart has regression lines built in; see RegressionDemo1 .
 
venkat xyz
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Thanks both of you for your help

@richard Reression seems to suit my requirement
Burt my plot having DateAxis as Domain axis and NumberAxis as range axis .
is it possible to calculate the Regression against above types.
 
Richard Tookey
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venkat xyz wrote:
Burt my plot having DateAxis as Domain axis and NumberAxis as range axis .
is it possible to calculate the Regression against above types.


I have not used it with domain as a date but you could look at the JFreeChart source code to find out if it copes. If it does not then it is easy enough to do write your own regression calculator. You can model this on the methods of Regression.java in JFreeChart. In general terms, to use regression using dates one just needs to convert the date to a number. A java.util.Date object contains the number of milliseconds since the epoch which may serve your purpose.
 
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