How to display discrete/noncontiguous data in series?

ibauer · Post by **ibauer** » Wed May 04, 2005 8:26 pm

Good evening!

I need to visualize a trend history of some process conditions in my system (using line series or similar). Bottom axis is intended to display TDateTime values (XValues) while left axis represents the actual value of a specific process condition (YValues) for the corresponding TDateTime.

When my application is running, it appends the new (current) values of all interesting process conditions to the log file in a regular time interval, so I can say that the data points contained in the log file that are used for visualization are equidistant.

The things get little complicated when my application is turned off (either intentionally by user or deliberately by a power outage) and launched again after some time. When this happens, the logging mechanism starts again to function but there is indeed a time gap between the last data point acquired just before the application was terminated and the first data point acquired right after the application has been restarted.

This time gap can easily be determined by subtracting every 2 consecutive xvalues and checking if the result is greater than regular sampling interval. What makes me pull my hair is that I don't know how to tell TeeChart to not draw the line between those 2 data points that surrounds the big time gap. Does anybody have any clue how to do it?

Thanks in advance!
Ivo

Narcís · Post by **Narcís** » Thu May 05, 2005 8:22 am

Hi Ivo,

This time gap can easily be determined by subtracting every 2 consecutive xvalues and checking if the result is greater than regular sampling interval. What makes me pull my hair is that I don't know how to tell TeeChart to not draw the line between those 2 data points that surrounds the big time gap. Does anybody have any clue how to do it?

You could use AddNull method to add null values for the gap values.

ibauer · Post by **ibauer** » Thu May 05, 2005 11:50 am

Hi, Narcís!

narcis wrote:You could use AddNull method to add null values for the gap values.

Thanks a lot. Adding a single null point between the two gap boundary points using AddNullXY did the trick! I supposed that this must be quite simple to accomplish with TeeChart.

Best regards,
Ivo