I've got an landscape A3 page in an A4 document, but the way I've written the code, it requires a blank page, or orients the previous page landscape too.

Also, is there an easy way to make this page not count in the page number count?

Many thanks!

\documentclass[titlepage,a4paper,12pt]{book}
\usepackage{graphicx}
\usepackage{rotating}
\usepackage{lscape}

\begin{itemize}
\item Carbon dioxide;
\item Temperature changes;
\item Global ice volume.
\end{itemize}

\begingroup

\pdfpagewidth=2\pdfpagewidth
\noindent%\makebox[0pt][l]{%
\pagestyle{empty}
\begin{landscape}

\begin{figure}[ht]
\centering
\includegraphics[width=0.95\linewidth]{BigFig.jpg}
\label{fig:locations}
\caption{TEXT}
\end{figure}

\end{landscape}

\endgroup

\end{document}


It occurred to me that what you really want is to make the entire page act as a float, rather than put a float into the page.

Changing the margins was harder than I thought. KOMA is obscure on the subject, and geometry forces a \newpage. Even when I reset all the parameters myself, things like \centering or \vfill don't work. I got \vfill to work by using a \vbox, or \hfill to work by using a \hbox, but not both at the same time.

I tried to use \NewEnviron, but \BODY and \afterpage don't work together. Lastly, I could not get the page number to show up on the next page, and eventually just overlayed the thing.

\documentclass{article}
\usepackage{geometry}
\usepackage{afterpage}
\usepackage{caption}% for \captionof
\usepackage{mwe}% for example-image (also loads lipsum and graphicx)

\newlength{\oldpaperheight}
\newlength{\oldpaperwidth}

\newcommand{\writepagenumber}%
{\raisebox{\dimexpr -\textheight-\footskip}[0pt][0pt]{\rlap{\makebox[\textwidth]{\thepage}}}}

\newcommand{\pagefloat}[2][1cm]% #1 = margin size (optional), #2 = contents
{\afterpage{%
\savegeometry{current}%
\thispagestyle{empty}%
\paperwidth=42cm
\eject \pdfpagewidth=\paperwidth \pdfpageheight=\paperheight
\topmargin=#1
\oddsidemargin=#1
\evensidemargin=\oddsidemargin
\linewidth=\paperwidth
\textheight=\paperheight
\textwidth=\linewidth% technically not in landscape
\noindent\vbox to \textheight{#2}%
\paperwidth=21cm
\eject \pdfpagewidth=\paperwidth \pdfpageheight=\paperheight
\noindent\null\writepagenumber
}}

\begin{document}

\pagefloat{%
\rule{\linewidth}{1pt}\vfill\par% show top of text area
\makebox[\linewidth][c]{\includegraphics[height=0.9\textheight]{example-image}}
\captionof{figure}{example image}
\vfill\par\rule{\linewidth}{1pt}% show bottom of text area
}

\lipsum[1-16]
\end{document}


This is the way I did it from looking at a similar question (I don't remember which one but if someone recognizes it then please give credit):

\usepackage{lscape}                     %allow certain pages to be formatted in landscape orientation
\usepackage[paper=A4,pagesize]{typearea}
\usepackage{afterpage}

\begin{document}
\afterpage{% Insert after the current page
\clearpage
\KOMAoptions{paper=A3,paper=landscape,pagesize}
\recalctypearea

%put stuff on A3 lanscape page here

\clearpage
\KOMAoptions{paper=A4,pagesize}
\recalctypearea
}
\pagebreak


For the page numbering you can use the \setcounter{page}{1} to reset the page counter on different pages (for example only start counting from after table of contents etc. Not sure how to miss a page though, maybe it will give you somewhere to look though