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\title{Figure Placement}
\author{}
\date{}

\maketitle

\noindent There are a few guidelines for figure placement that you
should follow.

\subheading{Figures should float}

\begin{quote}
Put your figures in a figure environment.  Do not just lay them into
the document in the midst of the text.
\end{quote}

Although putting your figures in the midst of the text might seem like
an ideal place, omitting the figure environment means that you cannot
insert a caption, nor can you refer to the figure by number.  So use
the figure environment.

``Ah-ha,'' you say, ``but the figure environment allows me to use the
\verb`[h]` option to place the figure right where I want it.  I get
the best of both worlds: captions and references, plus placement where
I want it.''

\begin{figure}[h]

\includegraphics{Dijkstra-proof.eps}

\figcaption{So there!}

\label{fig:here}

\end{figure}

\noindent You see, I can put Figure~\ref{fig:here} right here!
\medskip

One problem with using the \verb`[h]` option is that if your figure
doesn't fit on the current page, it will float to the top of the next
page anyway.

\begin{figure}[h]

\resizebox{!}{3in}{\includegraphics{Dijkstra-proof.eps}}

\figcaption{So there!}

\label{fig:big}

\end{figure}

\noindent So even though you think you put it ``here,'' it isn't here.
Here's some text that shows what happens.

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\bigskip

The other problem with using \verb`[h]` is that it can be hard to
determine where the division between the text and the figure is.

So let figures float.

\subheading{The default placement is usually pretty good}

It is rare that I have to override where \LaTeX{} places a figure.  Of
course, I have redefined several parameters in \~{ }thc/mytex/page.tex
so that \LaTeX{} is more willing to put figures at the top of a page.

In the entire book, which has 237 figures, we overrode the default
placement twice.  I just checked, and one of those was unnecessary.
The place where we needed to override was Figure~19.6 on page~467,
where I used \verb`[t]` to override \LaTeX{}'s desire to have that
figure be on its own page.

\subheading{Putting figures together}

Sometimes you have multiple figures that you really want to appear
consecutively.  If you put them in separate figure environments, they
might not appear together.

\begin{figure}

\scalebox{.8}{\includegraphics{flow-network.eps}}

\figcaption{\figpart{a} A flow network $G = (V,E)$ for the Lucky Puck
Company's trucking problem.  The Vancouver factory is the source $s$,
and the Winnipeg warehouse is the sink $t$.  Pucks are shipped through
intermediate cities, but only $c(u,v)$ crates per day can go from city
$u$ to city $v$.  Each edge is labeled with its capacity.  \figpart{b}
A flow $f$ in $G$ with value $\abs{f} = 19$.  Only positive flows are
shown.  If $f(u,v) > 0$, edge $(u,v)$ is labeled by $f(u,v)/c(u,v)$.
(The slash notation is used merely to separate the flow and capacity;
it does not indicate division.)  If $f(u,v) \leq 0$, edge $(u,v)$ is
labeled only by its capacity.}

\label{fig:flow-network}

\vspace*{6ex}

\scalebox{.8}{\includegraphics{residual-network.eps}}

\figcaption{\figpart{a} The flow network $G$ and flow $f$ of
Figure~\ref{fig:flow-network}(b).  \figpart{b} The residual network
$G_{f}$ with augmenting path $p$ shaded; its residual capacity is
$c_{f}(p) = c_{f}(v_2,v_3) = 4$.  \figpart{c} The flow in~$G$ that
results from augmenting along path $p$ by its residual capacity~$4$.
\figpart{d} The residual network induced by the flow in~(c).}

\label{fig:residual-network}

\end{figure}

No problem.  Put them in one figure environment.  You might need to
put some vspace between them.

\subheading{Where to put figures}

\LaTeX{}'s algorithm for determining where to put figures is explained
on pages 197--198 of Lamport.  The explanation is more clear than the
U.S. tax code.

Where a figure \emph{should} go is either on the first page that
mentions the figure, or on the next available page afterward.  There
is an exception, however.  If the figure is first mentioned near the
beginning of a section, and its placement at the top of the page
beginning the section would cause the figure to appear in the previous
section, then let the figure appear a page later.

Here's what \emph{I} do.  I put the figure environment right after the
first paragraph that mentions the figure.  90\% of the time, that
gives me exactly the placement I want.  On occasion, the figure will
appear on the next page, even though there is room on the page that
first mentions the figure.  That's because the mention is somewhere in
the middle of a paragraph and by the time you get to the end of the
paragraph, there's not enough room for the figure.  In these cases, I
move the figure environment just before the paragraph that first
mentions the figure.  If that puts the figure on the same page as the
first mention, mazel tov.  If not, then I don't worry about it.

\subheading{Pet peeve}

This pet peeve isn't about figure placement itself.  It's about
placement of the \emph{mention} of a figure.

Here's what I despite with every ounce of hemoglobin that I can
muster:
\begin{quote}
The [algorithm, procedure, method, system] works as
follows. [Looooooong explanation.]  Figure~4 shows an example.
\end{quote}

Thanks a lot!  After I've read your looooooong explanation,
\emph{then} you tell me there was a figure that would have helped me
understand what the heck you were trying to tell me?

Do your reader the courtesy of mentioning the figure \emph{before} the
long explanation:
\begin{quote}
Figure~4 shows how the [algorithm, procedure, method, system] works.
[Looooooong explanation.]
\end{quote}

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