Balancing Flexibility And Control: Handling Floats Gracefully In Latex Documents

Controlling Float Placement in LaTeX Documents

In LaTeX documents, images, tables, and other content that is not strictly part of the text flow are known as "floats". Properly positioning floats can be challenging for LaTeX due to the automated way pagination occurs. This article will discuss strategies for exerting finer control over float placement without sacrificing LaTeX's capability to handle positioning automatically in many cases.

The Floating Objects Problem in LaTeX

Unlike word processors, LaTeX does not position floats based on their location in the source document. Instead, it automatically moves floats to suitable locations on pages using a complex algorithm that considers available space, the number of floats waiting to be placed, whether a page may end up with too much white space, and various other factors. This approach allows LaTeX to produce beautifully typeset documents with optimal float placement. However, in some cases, the automated process causes floats to appear pages away from their first text reference or grouped at the end of a document instead of alongside relevant content. Specifying guidance for positioning floats can help mitigate these issues when LaTeX's default behavior is unsatisfactory.

How LaTeX Handles Floats by Default

By default, LaTeX gives preferential treatment to certain kinds of floats in determining placement order and location suitability. Higher priority floats like figures get set before tables, which LaTeX will more readily relegate to the end of a document or section if it runs short on good insertion points earlier on. LaTeX may also exhibit bias toward top area placement and recto pages. The exact handling depends on the loaded documentclass and packages affecting floats. Document elements like margin notes add further complexity. Overall though, LaTeX strives to avoid significant whitespace around or between floats to give documents a polished appearance. This automated approach works nicely for simpler documents but can make precise positioning of floats difficult in more complex cases.

Key Float Placement Options in LaTeX

H Option - Placing Floats Where Specified

The simplest way to control float placement is using the optional [H] location specifier when declaring a float object with {\textbackslash}begin. This positions the float right at the point of text reference instead of allowing LaTeX to locate it automatically. However, [H] should be used sparingly since it can significantly degrade page composition quality if overused in a document not designed to accommodate fixed float locations.

! Option - Forcing LaTeX to Place Floats

For floats like figures and tables that LaTeX has deferred placing due to lack of good insertion points, the {\textbackslash}begin option {!} exists to force output of waiting floats. LaTeX will accommodate floats marked with {!} even if it means unusually large white space between paragraphs. Because this impacts readability, {!} is best reserved only to unstick stubborn floats that remain unplaced after multiple natural reference points in the text.

p Option - Putting Floats on Float Pages

Another directive for controlling float placement is the "p" page location option. This sets LaTeX to position the marked object at the top area of a dedicated floats-only page instead of within normal text content. This approach prevents floats from breaking up body text while keeping related floats grouped. However, it can isolate some information away from the main discussion. The [p] option should be used thoughtfully after considering effects on reader comprehension of the material.

Positioning Floats with Package Options

In complex documents, manually tuning placement of every single float using low-level options like [H], {!}, and [p] becomes impractical. Fortunately, LaTeX offers packages that help take a programmatic approach to exerting finer control over positioning behavior.

[htbp] Package Option for Fine Control

The most flexible way of configuring float placement settings globally is to pass a [htbp] option when loading the float package. The four letters tunes treatment of floats in the whole document, with each position corresponding to a placement: h for "here", t for "top", b for "bottom", p for the separate "page". Unique combinations can force more preferential treatment for certain float types in different areas, like favoring bottom alignment for tables but not figures.

float Package for Extensive Float Customization

For ultimate control beyond [htbp] tweaks, the powerful float package contains dozens of parameters to separately define handling of figures, tables, algorithms and custom float types. Options exist to bias horizontal vs. vertical positioning, set priority for top/bottom areas, require text between floats, tune whitespace around and between floats, disable column-spanning landscape floats, and override LaTeX's float placement algorithms entirely with manual control.

When to Let LaTeX Handle Floats Itself

Despite various ways to override LaTeX's automated float placement engine, the smartest approach with simple documents is to avoid exerting much control initially. LaTeX has decades of typesetting wisdom built-in and usually does excellent job positioning floats itself in basic articles, reports, and books tuned for print output. Only upon noticing suboptimal placement patterns should light adjustments be made, stepping up to heavier package-based control for precision tuning once basic options no longer suffice. Letting LaTeX do what LaTeX does best yields good results in many cases.

Example LaTeX Codes for Common Float Handling Tasks

Some examples will demonstrate applying the float placement options discussed to address needs that often arise when finessing float positioning.

Keeping a Figure Near its First Reference

To place an image by text citing it without allowing surrounding whitespace:

Text discusses the concept shown in 
Figure~\ref{fig:concept}\begin{figure}[H]
  \includegraphics[width=\linewidth]{concept.png}
  \caption{Diagram of the concept under discussion}
  \label{fig:concept}
\end{figure}
which means...

Limiting Floats to the End of Sections

Configure floats to only appear at the end of sections:

\usepackage{float} 
\floatplacement{figure}{section}
\floatplacement{table}{section}

Sending All Tables to a Separate Appendix

Relegate tables to an appendix completely outside the text body:

\usepackage{placeins}
\let\OldTable\table
\renewcommand{\table}{\FloatBarrier\OldTable}
\begin{appendices}
  \section{Supplemental Tables}
  \processdelayedfloats
\end{appendices}

Achieving the Optimal Balance of Flexibility and Control

Skillful float placement lies between the extremes of forcing rigid positioning versus fully automated algorithms picking subpar locations. Learn to judiciously employ LaTeX's suite of float handling tools to exert just enough control to override undesirable default behavior when needed, while retaining enough flexibility to benefit from its automated typesetting capabilities otherwise.