Hello,

We have to implement a spectrogram type of plot. We need to display time on X-axis and frequency on Y-axis. The values need to be color coded with respect to the amplitude value.The color coding criteria should be displayed in the legend. For this I was evaluating the Grid Surface | Contour chart in Nevron examples.

An example of the spectrogram plot is in the attachment.

I have the following questions
1)Can we use the contour chart to implement the spectrogram?
2)The nevron example displays the X-axis and Depth axis. We want to display X and Y-axis.
3)In the nevron example,the method set value of NGridSurfaceData takes indexes as parameter which are of type integer. We would like to set date/time for X-axis and double values for Y-axis.
4)How can we display the color coding as a range of values in the legend. Ex: 0.1 - 25.3 Green, 50.3 - 100 Red.?

Thank you very much for answering these questions.

Best Regards,
Siraj

Hello Siraj,

Thank you for your interest in our chart control. Regarding your questions:

1. You can use either NGridSurfaceSeries or NMeshSurfaceSeries to display the spectrogram.

2. You can change the view so that the X axis is horizontal and the depth axis is vertical. The depth axis will still be called "Depth", but it will look like an Y axis. The "Chart Gallery > Grid Surface > Contour" example uses this approach.

3. In general there are two approaches. It depends on the actual data which one should be used. If your data is irregularly spaced in X (date-time) and Y (double) you have to use the NMeshSurfaceSeries. There you can set individual X, Y and Z values for each data point. If the data points are regularly spaced - you can use NGridSurfaceSeries.

4. The "Chart Gallery > Grid Surface > General" example demonstrates how to display a legend like the one that you described. If you want to display a gradient-like legend as the one on your image - you have to use another chart panel with a surface series that acts as a legend.

Best Regards,
Nevron Support Team