Next Previous Up Contents
Next: Plot Style Editor
Up: Graphics Windows
Previous: Histogram Style Editor

### A.4.3 2D Plot

Plot Window

The plot window allows you to do 2-dimensional scatter plots of one or more pair of table columns (or derived quantities). You can display it using the Plot () button in the Control Window's toolbar.

On the plotting surface a marker is plotted for each row in the selected dataset(s) at a position determined by the values in the table columns selected to provide the X and Y values. A marker will only be plotted if both the X and Y values are not blank. Select the quantities to plot and the plotting symbols with the dataset selector at the bottom. You can configure the axes, including zooming in and out, with the mouse (drag on the plot or the axes) or manually as described in Appendix A.4.1.2.

Clicking on any of the plotted points will activate it - see Section 8.

The following buttons are available on the toolbar:

Split Window
  Allows the dataset selector to be resized by dragging a separator between it and the plot area. Good for small screens.
Replot
  Redraws the current plot. It is usually not necessary to use this button, since if you change any of the plot characteristics with the controls in this window the plot will be redrawn automatically. However if you have changed the data, e.g. by editing cells in the Data Window, the plot is not automatically redrawn (since this is potentially an expensive operation and you may not require it). Clicking this button redraws the plot taking account of any changes to the table data.
Configure Axes and Title
  Pops up a dialogue to allow manual configuration of axis ranges, axis labels and plot title - see Appendix A.4.1.2.
Export as PDF
  Pops up a dialogue which will write the current plot as a PDF file. In general this is a faithful and high quality rendering of what is displayed in the plot window. However, if plotting is being done using the transparent markers, the markers will be rendered as if they were opaque. Plots with very many points can result in rather large output PDFs.
Export as GIF
  Pops up a dialogue which will output the current plot to a GIF file. The output file is just the same as the plotted image that you see. Resize the plotting window before the export to control the size of the output GIF.
Rescale
  Rescales the axes of the current plot so that it contains all the data points in the currently selected subsets. By default the plot will be scaled like this, but it it may have changed because of changes in the subset selection or from zooming in or out.
Grid
  Toggles whether a grid is drawn over the plotting surface or not.
Show Legend
  Toggles whether a legend showing how each data set is represented is visible to the right of the plot. Initially the legend is shown only if more than one data set is being shown at once.
Draw Subset Region
  Allows you to draw a region on the screen defining a new Row Subset. When you have finished drawing it, click this button again to indicate you're done. See Appendix A.4.1.6 for more details.
Subset From Visible
  Defines a new Row Subset consisting of only the points which are currently visible on the plotting surface. See Appendix A.4.1.6 for more explanation.

The Dataset Toolbar contains the following options:

/ Add/Remove dataset
  Adds/removes tabs in which the data for extra datasets can be entered. See Appendix A.4.1.1.
/ Add/Remove auxiliary axis
  Adds/removes a selector for entering an auxiliary axis to modify point colours etc. See Appendix A.4.1.5.
Toggle point labelling
  Allows text labels to be drawn near plotted points. See Appendix A.4.1.4.
/ Toggle X/Y error bars
  Switches between drawing symmetric error bars and no error bars in the X and Y directions respectively. Other options are available in the Errors menu. See Appendix A.4.1.3.

You have considerable freedom to configure how the points are plotted including the shape, colour and transparency of symbols, the type of lines which join them if any, and the representation of error bars if active. These options are described in the following subsection.

- A.4.3.1 Plot Style Editor

Next Previous Up Contents
Next: Plot Style Editor
Up: Graphics Windows
Previous: Histogram Style Editor

TOPCAT - Tool for OPerations on Catalogues And Tables
Starlink User Note253
TOPCAT web page: http://www.starlink.ac.uk/topcat/
Author email: m.b.taylor@bristol.ac.uk
Mailing list: topcat-user@bristol.ac.uk