Columns Window
The Columns Window displays a JTable
giving all the information (metadata)
known about each column in the table.
You can display it using the Column Info ()
button when the chosen table is selected in the
Control Window's Table List.
The display may take a little bit of getting used to, since each column in the main data table is represented by a row in the JTable displayed here. The order and widths of the columns of the JTable widget can be changed in the same way as those for the Data Window JTable, but this has no effect on the data.
The column on the left labelled Visible
contains a checkbox in each row (one for each column of the data table).
Initially, these are all ticked.
By clicking on those boxes, you can toggle them between ticked and
unticked. When unticked, the column in question will become hidden.
The row can still be seen in this window, but the corresponding data
column is no longer a part of
the Apparent Table, so will not be seen
in the Data Window or appear in
exported versions of the table.
You can tick/untick multiple columns at once by highlighting a set of
rows by dragging the mouse over them and then using the
Hide Selected () or
Reveal Selected (
)
toolbar buttons or menu items.
If you want to hide or reveal all the columns in the table, use the
Hide All (
) or
Reveal All (
) buttons.
Each column in the displayed JTable corresponds to one piece of information for each of the columns in the data table - column name, description, UCD etc. Tables of different types (e.g. ones read from different input formats) can have different categories of metadata. By default a metadata category is displayed in this JTable if at least one table column has a non-blank value for that metadata category, so for instance if no table columns have a defined UCD then the UCD column will not appear. Categories can be made to appear and disappear however by using the Display menu. The metadata items are as follows:
You can edit most of these items, e.g. to rename a column or change the expression defining a synthetic column, by double-clicking on them as usual.
By default, the order in which the rows are displayed is determined by the table's current Column Set. However, you can change the display order in this window by clicking on the column headers (in the same way as for some other JTables). The little up arrow at the top left of the scrolled JTable display indicates that the display is in its "natural" (Column Set) order, but by clicking on headers you can sort by column name, units UCD etc. Clicking sorts up, clicking again sorts down, and a third time (or clicking on the top left) restores natural order.
You can change the order of the columns in the Column Set by dragging the grey number cell at the left of the corresponding row up or down. Note however this is only possible for non-hidden columns, and it only works if this JTable is currently displayed either in its natural order or sorted by the Index column (see above) - dragging rows wouldn't have any effect if some other sort order was active. An alternative way to change Column Set order is to drag the column headers left or right in the Data Window.
A good way to find a column in the Data window if your table is too wide to do it by browsing is to sort the table in this window on some suitable item (e.g. Name, Units, UCD), scroll to the column of interest, and then click on it; that causes the view in the Data Window to scroll sideways so that the selected column is visible.
The following buttons are available in the toolbar:
float[]
representing magnitudes in 5 different bands,
then selecting it and hitting this button will hide PMAG and
insert 5 new Float
-type columns PMAG_1...PMAG_5
in its place each containing one of the magnitudes.
If the column does not have a fixed number of elements listed in
the Shape column of this window, this button is disabled.
In that case, if you know how many columns you want to explode it into,
you can enter that value into the Shape field by double-clicking on it.
This will only work for columns that are actually arrays.
Several of these actions operate on the currently selected column or columns. You can select columns by clicking on the corresponding row in the displayed JTable as usual. A side effect of selecting a single column is that the table view in the Data Window will be scrolled sideways so that the selected column is visible in (approximately) the middle of the screen. This can be a boon if you are dealing with a table that contains a large number of columns.