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#### A.4.5.6 Error Bars Form

The Error Bars form () draws symmetric or asymmetric error bars in some or all of the dimensions of a 1-, 2- or 3-dimensional Cartesian plot. The shape of the error "bars" is quite configurable, including (for 2- and 3-d errors) ellipses, rectangles etc, aligned with the axes (for rotated ellipses and rectangles, see the XYEllipse and XYCorr forms).

Example XYError plot

Error Bars form configuration panel

The configuration options are:

Shading Mode
  See Appendix A.4.6.
X Positive Error, X Negative Error, ...
  For each dimension of the plot, you can enter positive and/or negative error values as columns or expressions from the table. All of these values must be positive; any negative values will be ignored. If both positive and negative values are filled in for an axis, the errors will be asymmetric. If the negative value is blank (either because the coordinate is not filled in, or because its value is blank for that row), the error bars will be symmetric, i.e. the negative error bar will be the same size as the positive one. If you want to ensure only a positive error bar is plotted, enter "`0`" for the corresponding negative error.
Error Bar
  Error bar shape from a list of options. Exact appearance will also depend on the dimensionality of the supplied errors.
Thickness
  Controls the line thickness used when drawing error bars. Zero, the default value, means a 1-pixel-wide line is used. Larger values make drawn lines thicker, but note changing this value will not affect all shapes, for instance filled rectangles contain no line drawings.

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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@jiscmail.ac.uk