Customizing Latex Float Placements For Optimal Readability

Controlling LaTeX Float Placements

LaTeX gives automated control over the placement of figures and tables through its floating algorithm. However, this can sometimes lead to less than ideal placements that negatively impact readers. Controlling float behavior is key to a smooth reading experience.

The Problem of Figures and Tables Floating to Undesirable Locations

LaTeX floats like figures and tables are placed according to an algorithm that determines the optimal position based on the size of the float and the available space on the page. However, this can result in floats appearing pages away from where they are first referenced. Additionally, they may disrupt logical text flow or stack up in inconvenient ways.

For example, it is suboptimal to introduce a concept then direct readers to a figure 5 pages away for a key visualization illustrating it. Likewise, having multiple figures or tables cluster together leaves awkward gaps in surrounding text.

Table of Contents

Understanding LaTeX’s Float Placement Algorithms

The Concept of “Float Areas” on a Page

For positioning floats, LaTeX divides pages into potential float areas. It aims to assign floats to float areas where they fit best without violating certain constraints that negatively impact readability.

Some key constraints are:

Floats cannot appear before they are first referenced in the text body unless the reference appears on the same page.
Two floats cannot appear next to each other at the top or bottom of a page.
Text cannot “run out” a page with less than 2 lines remaining after a newly placed float without attempting to balance to the next page.

LaTeX tries to balance meeting these constraints with fitting bigger or multiple floats onto the same page for efficient use of space.

How LaTeX Decides on Placements

The LaTeX float positioning algorithm works in a multi-pass approach. On each pass, it tests all possible float areas in sequence and evaluates if a candidate float fits there without violating constraints.

The order for checking float areas is:

On its own page after being first referenced [p]
In the top area of the page [t]
In the bottom area of the page [b]
On the next page if it fits there to avoid [h] for “here”
Specifically where first referenced [h]

Once a working placement is found, the algorithm moves on to positioning the next float. This cycle continues until all floats are placed or no more can be legally positioned.

Float Placement Options

The [h] Option to Try to Place Here First

By default LaTeX will only try placing a float where it is first referenced after checking other float areas first. If you specifically want a float like a figure or table to try to go first in that exact spot, you can use the [h] location modifier.

For example, to make Figure 1 attempt to directly place where referenced before considering other float areas:

  
\begin{figure}[h]
  \includegraphics{figure1.png}`
  \caption{Figure 1}
\end{figure}

The [t] and [b] Options for Forcing Top or Bottom

LaTeX decides on float placement based on a set of rules for optimizing page real estate. However, sometimes you may want explicit control to force a float to the top or bottom of a float area over LaTeX choosing on its own.

The [t] modifier tells LaTeX to strictly place a float only at the top of a page. Likewise, [b] forces the bottom. If LaTeX cannot legally place it there without violating constraints, the float will be moved later.

As an example, this table would try to go top first before considering other options:

\begin{table}[t]
  \begin{tabular}{|l|l|}
  \hline
    Column 1 & Column 2\\ 
  \hline
  \end{tabular}
  \caption{Table forced to attempt top first with [t].}  
\end{table}

The [p] Option for Moving to a Separate Float Page

For wide floats that occupy significant page space, LaTeX may have difficulty finding a legal position that won’t violate text spacing rules. By specifying the [p] page placement modifier, you can tell LaTeX to move such problematic floats to their own dedicated float page.

These page floats act as a catch-all overflow when no inline placement works. The [p] option overrides most other constraints so can automatically resolve tough spacing issues.

Advanced Float Customization

The float Package for More Control

While basic options like [h], [t] and [b] provide some degree of float placement control, the LaTeX float package opens up deeper customizations.

After including \usepackage{float}, new enhanced placement specifiers become available like:

H – Try harder to strictly place the float here without considering other areas first
endfloat – Postpone placement until end of chapter or section instead of floating earlier
ruled – Create floats that span both margins with custom positional rules

Plus fine-grained control mechanisms for manual float spacing, collaboration with same-type floats, and explicit float numbering.

Defining Custom Float Areas

Standard LaTeX defines certain float areas like t, b or p. To override the defaults and specify new custom float areas, you can configure the \topfraction, \bottomfraction and \textfraction counters.

For example, to ensure at least 40 lines between top area floats by reserving the upper 30% of a page:

\setcounter{topfraction}{0.7}  
\setcounter{bottomfraction}{0.8}  
\setcounter{textfraction}{0.2}

Now LaTeX will abide by the newly defined locations rather than its default spacing rules for positioning floats.

Forcing Floats to Appear Together

LaTeX normally avoids placing different float types directly adjacent. However tables and figures that relate to the same concept can override this with the \FloatBarrier command from the cuted package.

For example:

\begin{figure}[htbp]
  \includegraphics{result1.png}
\end{figure}

\begin{table}[htbp]
  \caption{Result 1 Data}
  \begin{tabular}{|l|l|} 
  ...
\end{tabular} 
\end{table}

\FloatBarrier

\begin{figure}[htbp]
  \includegraphics{result2.png} 
\end{figure}

\begin{table}[htbp]
...\end{table}

Inserts a barrier after related Figure and Table floats, allowing the pairs to remain together that otherwise LaTeX may separate.

Achieving Harmony Between Floats and Text

Balancing LaTeX's automated float placement against readability needs manual care. There are further useful guidelines for harmonizing floats with surrounding text:

Place all floats sequentially at the first text reference location instead of allowing scattered placements across chapters or sections for easier context.
Set the global counter \floatpagefraction to 0.7+ to minimize isolated floats forcing dedicated float pages away from references.
Limit floats embedded directly in paragraphs by increasing the \intextsep counter that controls spacing.
Surround groups of collaborating floats with custom rules using the \FloatBarrier command to prevent type mixing.

There are unavoidable edge cases where LaTeX cannot find an optimal position without conflicting rules. But in most cases, the float and text flow can align well by applying a defense-in-depth strategy using the range of configuration options.

Example Code Snippets for Common Scenarios

Here are some reusable examples for frequently needed float customizations:

Forcing Strict Top First Placement

\begin{figure}[H]
  ... 
\end{figure}

The H option tries harder to place on 1st reference before considering other areas.

Preventing Isolated Float Pages

\setcounter{floatpagefraction}{0.7}

Increases threshold before allowing singles floats to consume a dedicated page.

Aligning Collaborating Table and Figure

  
\begin{figure}[h]
  ...
\end{figure}

\begin{table}[h]
...\end{table}  

\FloatBarrier

Barrier command prevents LaTeX separating related floats.

Reserving Space for a Long Table

\begin{table}[p]
  \begin{longtable}{|p{3cm}|p{3cm}|}
  ...
\end{longtable}
\end{table}

Long table forced onto its own page by [p] to avoid constrained inline placement.

FAQs on Troubleshooting Float Placements

Why do my tables and figures ignore modifiers like [h] or [t]?

LaTeX ignores illegal placements that violate constraints. Use \clearpage before a problematic float to start fresh positioning.

Multiple floats are clustering together though I have room?

LaTeX avoids floats touching bottom and top simultaneously. But [t] and [b] together can legally override.

How can I prevent text skipping pages due to floats?

Set \raggedbottom to not overstretch pages. Allow optional end-of-page floats by reducing \intextsep.

Can I manually position a float using coordinates?

Yes, the float package supports absolute positioning with \begin{figure}[H] \floatbox[{\Xhpos{3cm}\Yvpos{3cm}}]{...} for x and y control.