The Table layer control ()
is available for all the plot types.
Use the Layers menu item or corresponding toolbar button to
add an instance to the control stack.
This is the control which is used for most of the data plotting in the layer plot windows. Each instance of this control in the stack does plotting for a particular set of positions from a single table. The set of positions is defined in the Positions tab as a column name or expression for each plot coordinate (e.g. for X and Y in a plane plot). However, the control can generate multiple layers from these positions; the Subsets tab controls which subsets are plotted and how each one is identified, and the Form tab provides many options for what graphics will be plotted based on the positions.
The three tabs, Position, Subsets and Form, are described in more detail below.
Position tab of Table layer control
In the Position tab you enter the base positions for each plotted point. This generally means selecting a table and providing a value (table column or expression) for each positional coordinate. When you first open a plot window, TOPCAT gives you a table layer control by default, and attempts to fill in the positional coordinates with some reasonable values from the table (for instance the first few numeric columns).
Subsets tab of Table layer control
The Subsets tab lists the defined Row Subsets for the table you have selected in the Position tab. The subset All is always present; others may or may not be depending on whether any have been defined. Note that actions you take in the plot (for instance selecting a new subset by region) can result in new entries being added to this list.
The list on the left names the subsets with an activation checkbox and a grab handle; the panel on the right gives the detail for the currently selected subset. Select a subset to see/change its detail by clicking on it.
For each subset you can select:
Form tab of Table layer control
The Form tab lets you define how each data set is plotted. The list on the left gives a list of forms currently being plotted, and the panel on the right shows the detailed configuration for the currently selected form.
When first added, the list contains a single entry, Mark,
which plots a marker of a given fixed shape and size.
The colour is by default determined by the setting in the Subsets tab.
For a simple scatter plot, this is all that you need.
However, there are a number of other forms that you can plot as well
or instead of the simple markers - vectors, error bars, ellipses,
contours, text markers etc. You add a new form to the stack by
clicking on one of the buttons in the toolbar in the tab.
You can remove a form with the Remove ()
button in the same toolbar. You can also activate/deactivate them
with the checkbox and move them up and down with the drag handle as usual.
The list of forms that are avaiable depends on the plot type;
the full list is in Appendix A.5.5.
The detail panel of each form depends on the form itself. It is divided into the following panels, though not all forms have all the panels.