7. Floats

Figures and tables are referred to as “floats” because they are floated to the nearest location. This prevents ugly large spaces appearing on the page if there isn't enough room for the figure or table before the page break. Floats have a caption and associated number[The style of captions]. It is customary for captions to appear at the bottom of figures but at the top of tables [17,11].

For both figures and tables, the caption is generated using the command:

\caption[<short caption>]{<text>}

Note that the \caption command has a moving argument, so fragile commands [Footnotes in captions] will need to be protected using \protect. The optional argument <short caption> is used to provide an alternative shorter caption for the list of figures or list of tables, akin to the optional argument to the sectioning commands.

Note:

Although the \caption command can have an optional short title, in general, captions should be brief. They should not contain lots of description or background detail [17]. That type of information should be placed in the main text not the caption.

Positioning:

[Wide figures in two-column documents]Both the figure and table environments have an optional argument <placement specifiers>, which indicates permissible locations for the float. This may be a combination of h (“here”), t (top), b (bottom) and p (page of floats.) Note that this only gives a general guideline as to where the float will end up. The final location is governed by other factors, such as space left on the page and the proportion of text to floats on the page. If you omit one or more of the placement specifiers, then you are prohibiting the float from being placed in that location. A common mistake is to do

✘ \begin{figure}[h]

which says “I want the figure here and it can't go anywhere else!” If the figure can't be placed exactly here (for example, there may not be enough room on the page), then you have given it no alternative location, which can result in this and all subsequent figures being dumped at the end of the chapter or document, or can result in a fatal error when running LaTeX[“Too many unprocessed floats”]. You may be able to manage with only one of the other options, for example,

\begin{figure}[t]

(In fact, modern TeX distributions now replace [h] with [t] if the float can't be placed.) However, if you have a large number of floats it is advisable to provide as many options as possible:

\begin{figure}[htbp]

Similarly for tables.

If you are absolutely adamant that an image must go “right here”, then it's not a float, and you shouldn't be using the figure environment. It's just a horizontal box, like the example earlier. Similarly for tabulated material.

It's worth bearing in mind what the Oxford Style Manual [11] has to say:

“Text must not be read into it so as to give [the figure] an explicit and fixed introduction, for example ‘in the following figure’: the final placement is determined by page breaks, which cannot be anticipated before setting, and this makes rewording the text necessary if the illustration does not fit the make-up of the page.”

Turabian [17] gives the same advice (and reiterates it for figures):

“All text references to a table should be by a number, not by an introductory phrase such as ‘in the following table’.”

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