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Append Data

The append process adds data from one or more data files to an existing data set in Windographer. Use File > Append to access this feature.

Mapping Data Columns

You can use the append facility to add data to the existing data columns, or to add new data columns, or to do both at once. You control the process by mapping the new data columns to the existing data columns, telling Windographer whether to put the new data in the data columns that already exist in the master data set, or to create new data columns to contain the new data.

The drop-down boxes on the right side of the window allow you to map the appended data columns to new or existing data columns as appropriate. The mapping shown in the screenshot below tells Windographer to put data from the appended data file's 'Speed 20m' data column into the master data file's existing data column by the same name. (Highlighted in red.) It also tells Windographer to put data from the appended data file's 'Direction 56m' data column into a new data column in the master data set. (Highlighted in purple.)

Example column mapping for append process in Windographer

Adding to the Existing Data Columns

Since data loggers typically create one data file per day or one per month, data analysts 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 data set, then appending the other data files to that master data set using File > Append. In this case, the append process will "add rows" to the existing data set, as the diagram below illustrates:

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. As long as the time step of the appended data matches that of the master data set, Windographer will place the new data in the correct chronological order, and it will adjust the start or end date of the main data set if necessary.

Adding New Data Columns

At other times you many need to combine two data sets into one, for example to combine a SoDAR data set with a met tower data set. You can do this by appending one data set into the other, so as to "add columns" to the master data set, as the diagram below illustrates:

The column mapping to accomplish this would look like so:

Data Coverage Chart

Below the column map diagram appears a data coverage chart showing the time spans covered by the master data set and the data set you are about to append. If the appended data set starts follows immediately after the master data set, the data coverage chart will look something like this:

If the appended data set overlaps part of the master data set, the data coverage chart will look something like this:

Note that in this window, the data coverage chart only indicates start and end dates, without indicating gaps.

Appending Overlapping Data

If the master and appended data sets overlap in time, and if you have mapped one or more appended data column to an existing data column, Windographer will refer to the Overwrite settings to decide how to handle the overlapping data. You can specify that the appended data always overwrites the existing data, or that it never does. Another alternative is to overwrite existing data only where the existing data is missing. In that case, the appended data can fill gaps in the existing data, but no existing data values will be overwritten. A fourth alternative is to overwrite existing data at all times except where the appended data is missing.

Tip: You can specify the default overwrite setting in Tools > Options.

Saving and Remembering Settings

Click Save Settings to save all the settings in this window to a file that you can then load at a later date when appending data to the same master data set or some other master data set. The stored settings include the column mapping and the overwrite settings. Note that Windographer stores the column mapping information numerically, for example the first appended data column maps to the third master data column. It does not store column names.

If you want to store the settings for the next time you append data to the current master data set, simply check the Remember settings checkbox before clicking OK:

Then Windographer will save the settings within the .windog file and automatically apply them when you append data to that file in the future. This can save time in a case where you repeatedly append new data files as they become available, but their data structure differs from that of the master data set. This can occur, for example, when you change the instrument arrangement on a meteorological tower so that it now has a different number of sensors than before, or one sensor is at at different height than before.

Appending .windog Files

When you append a .windog file, Windographer will append both the numeric data and the flagged segments from the appended file. If the appended file has some data segments in January flagged with the 'Icing' flag, Windographer will append the January data according to the append overwrite settings, but it will append the flag and flagged segment information regardless of the overwrite settings. Any new flags that appear in the appended file will be added to the master file. Windographer will not import the document history or flag rules from the appended file.

Appending Multiple Files

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

When you select multiple files to append, Windographer will assume that they all share the same data structure. so the Append Data Set window will appear only once.