Synchronizing Points in Time

Select Reference Time Series to Synchronize

If you select a Reference Time Series for synchronization, its time axis becomes the basis for synchronization. Only one time series can be selected as reference at a time. In the drop-down list, select the time series with the desired time points. You can choose from all time series opened in the ETA.

Then Select time series to be synchronized, whereby multiple selection is possible (see following figure).

In the event that additional time points in the synchronized time series need to be calculated, the calculation method shall be determined. Depending on the method selected, the result time series receives corresponding data points at the additional times specified by the reference time series. As a result, the reference time series and the synchronized time series have the same number of data points. The data points are located at exactly the same time points (times of day).

Finally, specify whether the existing time series is to be overwritten with the synchronized time series or whether a new time series is to be created.

Assemble Time Series

If the Assemble time series method is selected, the drop-down list for selecting the reference time series is deactivated. Under Select time series to be synchronized, you can select one or more time series to be synchronized.

In the next steps, the synchronization procedure is selected in the same way as when using a reference time series and it is determined whether the existing time series are to be overwritten with the synchronized time series or whether new time series are to be created.

Depending on the method selected, the result time series receive corresponding data points at the additional time points. The points of time of all time series selected for synchronization are taken into account. As a result, an associated synchronized output time series is obtained for each input time series.

Synchronization Method

You can choose between Preserving Integral, Linear Interpolation, Spline Interpolation, Moving Average, and Default Values.

Preserve Integral

This method calculates the new values in such a way that the integrals of the output time series and the time series to be synchronized match in the synchronized time period. The following figure schematically illustrates the integral-maintaining synchronization.

The integral-preserving method is preferable, for example, for heat or electric power time series (process variables) because the integral energy quantity is preserved.

Linear Interpolation

When synchronizing using linear interpolation, data are inserted at missing points in time on a connecting line between the existing previous value and the next value. The following figure schematically illustrates the synchronization by means of linear interpolation.

Linear interpolation is suitable, for example, for temperature time series (state variables) because there is a relationship between the previous and future points in time.

Spline Interpolation

Synchronization using cubic spline interpolation inserts data along a connection curve between the previous and next existing value at missing points in time. The following figure schematically illustrates synchronization using cubic spline interpolation.

Moving Average

The method Moving Average calculates the mean value from any number of previous and subsequent values of the original time series for each missing point in time of a time series. The following figure illustrates the synchronization with average values schematically using the example n_pre = n_post = 2.

Default Value

A certain Default Value can be entered as a substitute value for the new times. If the input field is left empty, empty data points (NaNs) are inserted. The following figure illustrates the synchronization with predefined values schematically.