polar chart

[Rolf Fankhauser]

Hi all,

I have some questions concerning polar charts:

- How can I achieve that the height and width of the chart is always equal i.e. that a circle is drawn and not an ellipsis independent of the outer bounds of the chart?
- Can I activate paging for a polar chart? I tried it but it didn't work. I set MaxPointsPerPage = 28 and used a ChartPageNavigator component but I see always all points.

Thanks in advance for any help.

Kind regards, Rolf

I use TeeChart Pro v5.03

[Narcís]

Hi Rolf,

- How can I achieve that the height and width of the chart is always equal i.e. that a circle is drawn and not an ellipsis independent of the outer bounds of the chart?

Yes, you can use Circled property:

Code: Select all

  Series1.Circled:=true;

- Can I activate paging for a polar chart? I tried it but it didn't work. I set MaxPointsPerPage = 28 and used a ChartPageNavigator component but I see always all points.

I don't think TeeChart's paging feature is designed for Polar series. How would you expect this to work in such series?

Thanks in advance.

[Rolf Fankhauser]

Hi Narcis,

Thanks for the answer. I also found in the meantime the property Circled. I wonder that it is a property of the series and not of the chart.

Concerning your question about paging: I have data from a rotating wheel. Data is measured 28 times per revolution for constant angles i/28*360 degrees. So, I would like to see the data for each revolution, i.e. the first 28 points on the first page, the second 28 points and the second page and so on. One file consists of data from around 200 revolutions.
Afterwards I calculate average values for each measured angle and plot it over the data.

First, I tried to create a real time chart by reading the data from a file, add a point, wait some time with Sleep(), add the next point, wait some time and so on. I added a ProcessMessages() statement in order to redraw the chart. But after 100 revolutions (with a lot of points) it becomes rather slow. I guess that the redraw of the chart takes too long. Is there somewhere an example for real time charting? I also know the time between the samples (20 - 50 ms), so I would like to wait this time before drawing the next point.

I could simulate the paging by attaching the series to a data source that contains only the desired 28 points which I want to see. On page changing I would fill the data source with the next 28 points and so on. But maybe you know a easier solution.

Thanks, Rolf

[Narcís]

Hi Rolf,

Thanks for the information. In that case I recommend you to have a look at the Real-time charting article here. It may also help looking at the All Features\Welcome!\Speed examples in the new features demo, available at TeeChart's program group.

You could also try using a datasource as you mention then you'd only need to call series' CheckDataSource method every time you want to refresh it.

Hope this helps!