Inappropriate Null Data Representation in Function Series

[Seth]

Hi, supporters.

We are using TeeChart ActiveX v7.0.1.0 for our product, Report Designer.

We have encountered below three problems when using Exp.Moving Average Function Series with NULL values. We are posting this matter on the forum since we haven’t received any response form you although we already sent a Pro Priority Question email on 11th of Oct.

1. It appears null values are treated as if they have numeric values of 0 by Exp.Moving Average Function Series. We’d like to know whether a Function Series can be represented without being aversely affected by null data.

Symptom: When S0 Line Series represents the Source data whereas MA5 shows Exp.Moving Average Function Series, the MA5 Series graph drops dramatically when it deals with null data.

We know null values are received as null but represented as if they are 0 with invisible RGB value (assuming white).

FYI. The setting is as follows; Calculate using: Every number of points / Number of points:5 / Alignment: Center

2. Is it possible to have Min/Max scale of Left Axis without reflecting null values but effective values?

In fact, the minimum value of S0 Series should be set at about 350 instead of 0.

We assume that this is caused by assumed 0 numeric values when the values are, in fact, null.

3. Is there any readily available API function that refreshes the Function series after all the source data are properly loaded when a Function series is added beforehand?

Symptom: When a user opens the Editing dialog box after loading all the data to the Source series by using Add function, she can see the Function Series is stored but it is not updated according to the source data. The Function Series is refreshed only after a user changes the values of ‘Number of points’ in Data Source and clicks on the Apply button.

We believe there must be an API function that redraws all the Function series but haven’t found it yet. Is there?

Regard,

[Narcís]

Hi Seth,

Please find below the answers to your questions:

1. Not all functions support null values excluding. The only way to achieve that would be iterating through all points in a series cheching which of them are null (isNull()). If so then remove them or copy them to dummy series and assign it to the function datasource.
Another option would be using AddNullXY setting the same values as the point before and set the color to clNone to make this point not visible.

2. Solving problem 1 will solve this point. However you can use axes SetMinMax method or axes Minimum property to set the values you want.

3. Yes, this is possible using Series.CheckDataSource method.

[Seth]

Hi, Narcís

Thank you for your swift answer.

With regard to the null data representation, unfortunately, your answer did not provide us with any tangible solution or answer at all. So, we are presenting a sample to facilitate your understanding of the matter. We will be thankful if you provide us with relevant answer for the matter. Please, also refer to the Visual Basic source file and image you can download from below link.
http://www.m2soft.co.kr/report/edward/V ... (7010).zip
http://www.m2soft.co.kr/report/edward/E ... nction.jpg

Best Regards,
Seth

[Narcís]

Hi Seth,

I'm afraid this project doesn't reproduce the problem you reported as it contains a simple pie series. Could you please check this and post the project you mentioned?

Thanks in advance.

[Seth]

Dear Narcís

Thank you for such a quick response.

I am really sorry to have made such a mistake.
Here, I am posting a download link to the actual VB Project file.

http://www.m2soft.co.kr/report/edward/vbsample.zip

Thank you in advance for your help.
Have a nice weekend.

Best Regards,
Seth

[Narcís]

Hello Seth,

No problem. I've modified your project with the solutions I commented and sent them to you.

Thanks and have a nice weekend too.