Appending Data

The append process adds data from one or more data files to an existing dataset. To append data, choose Append or Append Folder from the File menu.

Two Types of Appending

If we think of a time series dataset as a table of data, with rows corresponding to time steps and columns corresponding to data columns, then we can describe the two types of appending as 'adding rows' and 'adding colums'. To 'add rows' is to append more time steps onto existing data columns, for example by adding a new day of data to a dataset you've been building up. To 'add columns' is to append additional data columns to an existing dataset, for example by appending a met tower dataset to a wind turbine SCADA dataset.

Adding to the Existing Data Columns

Since data loggers typically create one data file per day, analysts very often need to aggregate multiple data files that all share the same data structure. In Windographer, you can accomplish this by opening one of the data files with File > Open to establish a master dataset, then appending the other data files to that master dataset using File > Append. In this case, the append process will 'add rows' to the master dataset, as the diagram below illustrates:

In the Append Settings window the column mapping to accomplish this would look like so:

Tip: In this example, the appended time steps follow immediately after the existing time steps with no gap and no overlap, but the append process can also handle scenarios where the new data precedes or overlaps with the existing data, or a gap separates the new data from the existing data. Windographer will place the new data in the correct chronological order, and it will adjust the start or end date of the main dataset as necessary.

Adding New Data Columns

At other times you many need to combine two datasets into one, for example to combine a LiDAR or SoDAR dataset together with a met tower dataset. You can do this by appending one dataset into the other, so as to 'add columns' to the master dataset, as the diagram below illustrates:

The column mapping to accomplish this would look like so:

Appending Multiple Files

In the Append One or More Files window, you can select multiple files by holding down the Shift key or the Ctrl key when you click on files:

Another approach is to use File > Append Folder and select an entire folder of files:

When you append multiple files, Windographer updates the Append Status window as it works on each file, and provides details on such as whether it was successfully appended, how many time steps it contained, and whether it represented a data structure change:

For the first file that you append, and anytime the data in the appended file conflicts with the master dataset, Windographer will display the Append Settings window so that you can specify where to put the new data and how to resolve any conflicts.

Appending windog Files

When you append a .windog file, Windographer will not import the dataset history, flag rules, or calculated columns from the appended file. If you wish to retain the calculated columns in a particular file you plan to append, you could instead use that file as the master file, and append another .windog file to it.