BIRT Exchange Forum: BIRT Exchange Forum -> Last Week in the Forums: Creating a "Top N and Other" Pie Chart, Adding Row Dimension Headers to a Crosstab, and more...

This blog series takes a look back at the past week in the forums, recalling how active they were and highlights some of the questions asked that seem to frequent the forums or other interesting topics. The BIRT Exchange forums continue to be busy as we push towards August. There is lots more help from members answering questions these days too. Thanks to those members who are providing these answers. It is a great help to the community!

The first topic for this week is about creating a "top n" pie chart, with the rest of the slices being combined into a slice called "other". The poster was wanting to create a pie chart that showed the top 5 slices and then combine the rest in to a slice called "other". There is a minimum slice setting for a pie chart that allows you to set a minimum value and combine the ones that don't meet that value and call them "other". However, this doesn't work if you're wanting a top 5 with dynamic data. You don't know what the minimum slice should be. I'm sure there is a way to script this in your chart script too, but the solution provided to this question was to use a couple computed columns to find the top 5 values in the dataSet and to define the category of "other" to those that don't fall in the top 5. Then, you can use these columns in the chart instead. An example is provided in the forum thread.

The second topic I'll discuss this week is about adding row dimension headers to a crosstab. The poster was wanting to add header labels to the upper left cell in a crosstab but was having issues doing so. The solution provided was to first add a grid and add the labels inside of this. To get them to line up properly with the columns below, you need to set the width of the grid cells and the width of the crosstab cells to match.

The last topic I'll cover is about adding "future" data to your dataSet based on a trend line so it can be plotted. The poster had an issue where they wanted to extend the data in their dataSet based on a trend line and plot it so they could visualize whether they would meet a certain threshold in the next 10-20% of data if the current trend were to continue. The example used in the thread was CPU usage. There were several days worth of data and a threshold parameter supplied by the user. If there were 10 days of data, the poster was wanting the trend data to extend an extra 2 days to see if the threshold would be met at the current rate. The solution provided was to use a scripted dataSet to compute the slope of the trend line and to use this to extend the trend line data out the extra 20%. The data was then available in the scripted dataSet to plot with a chart. An example is included in the thread showing how this was done.

Again, this is just a small sample of what went through the forums this past week. For more questions and answers that have been posted, check out the forums. As always, if you have a question, feel free to ask it, and if you see a question you know the answer to or have a similar experience to, feel free to post an answer or comment.