First the bad news:
You are correct that as implemented two-column floats are never inserted on the page on which their definition falls. Actually most people find this isn't a problem in practice as the figure*
environment doesn't need to be near the first \ref
to the figure, however it would be good not to have that restriction.
It would in fact be relatively easy to allow floats to float to the top if they fell in the first column using the same mechanism as the single column case, however the problem is that if the definition falls in the second column then the first column has already been set and saved in a box of full height and so the full width float can not be added.
Now the good news
LaTeX is a very open system, not only is it open source so you can look at the source and change things, its code is modifiable from within the document itself. Any document can redefine any latex definition.
The code below shows how you can automate the insertion of a figure definition on the page before the first reference, so that it is positioned at the top of the page with teh reference.
As posted below it only works with one figure but it would be easy to extend this with some declarative macros so that each figure was added to a list to be inserted as needed.
(But it's late and I wanted to show the result of a few minutes tinkering). So while the code below probably isn't production ready it does I hope show that you shouldn't abandon the idea of using LaTeX just because of some perceived restrictions. Other alternative systems may well have restrictions that they don't document so well and that are harder to work round:-)
\documentclass[12pt, twocolumn]{article}
\usepackage{lipsum}
\output\expandafter{\the\output\floatfix}
\makeatletter
\def\floatfix{%
\expandafter\ifx\csname r@x@one\endcsname\relax
\else
\ifnum\c@page=\numexpr\expandafter\expandafter\expandafter
\@secondoftwo\csname r@x@one\endcsname-1\relax
\aftergroup\figone
\fi
\fi}
\makeatother
\begin{document}
\section*{Introduction}
\def\figone{%
\begin{figure*}[tbph]
\makebox[\textwidth]{\framebox[5cm]{\rule{0pt}{5cm}}}
\caption{And here is the actual figure.
\label{one}}
\end{figure*}
\global\let\figone\relax}
\setlipsumdefault{13-19}
\lipsum
\textbf{Here is where I reference Figure~\ref{one}\label{x@one}}
\lipsum
\end{document}
I just ran into the same issue. (It's really annoying when trying to produce print-quality preprint versions of the paper.) Poking around in pnastwo.cls, I found the following fix:
Find the first line in pnastwo.cls which says
\ifx\@captype\xtable
Change this to
\ifx\@captype\table
Alternatively, if you don't want to touch the class file, you can
put the following into the preamble of your document:
% Fix wierd behavior which prevents table captions from appearing for
% tables in the body of the article
\makeatletter
\long\def\@makecaption#1#2{%
\ifx\@captype\table
\let\currtabcaption\relax
\gdef\currtabcaption{
\tabnumfont\relax #1. \tabtextfont\relax#2\par
\vskip\belowcaptionskip
}
\else
\vskip\abovecaptionskip
\sbox\@tempboxa{\fignumfont#1.\figtextfont\hskip.5em\relax #2}%
\ifdim \wd\@tempboxa >\hsize
\fignumfont\relax #1.\figtextfont\hskip.5em\relax#2\par
\else
\global \@minipagefalse
\hb@xt@\hsize{\hfil\box\@tempboxa\hfil}%
\fi
\fi
}
\makeatother
One additional comment: once this bug is fixed, you'll almost certainly run into another issue which you'd want fixed if you use the PNAS two-column class to produce production-quality output: Unless you define floats with the h "here" placement, it loses the labels, so all cross-referencing of figures and tables breaks. Here is the fix, for direct pasting into the document preamble. You can also patch up the macro \DonormalEndcol pnastwo.cls, it's the same mistake 6 times over...
% And another fix. PNAS class loses the label of floats unless they
% were defined with the [h] option (so not really floats at all). It
% all comes down to wrong scope in the following routine which pushes
% out the floats onto the page. This is the fixed version:
\makeatletter
\def\DonormalEndcol{%
%% top float ==>
\ifx\toporbotfloat\xtopfloat%
%% figure ==>
\ifcaptypefig%
\expandafter\gdef\csname topfloat\the\figandtabnumber\endcsname{%
\vbox{\vskip\PushOneColTopFig%
\unvbox\csname figandtabbox\the\loopnum\endcsname%
\vskip\abovefigcaptionskip%
\csname caption\the\loopnum\endcsname%
\csname letteredcaption\the\loopnum\endcsname%
\csname continuedcaption\the\loopnum\endcsname%
\csname letteredcontcaption\the\loopnum\endcsname
\ifredefining%
\csname label\the\loopnum\endcsname%
\expandafter\gdef\csname topfloat\the\loopnum\endcsname{}\fi}%
\vskip\intextfloatskip%%
\vskip-4pt %% probably an artifact of topskip??
}%
\else%
%% plate ==>
\ifcaptypeplate%
\expandafter\gdef\csname topfloat\the\figandtabnumber\endcsname{%
\vbox{\vskip\PushOneColTopFig%
\unvbox\csname figandtabbox\the\loopnum\endcsname
\vskip\abovefigcaptionskip
\csname caption\the\loopnum\endcsname
\csname letteredcaption\the\loopnum\endcsname
\csname continuedcaption\the\loopnum\endcsname
\csname letteredcontcaption\the\loopnum\endcsname
\ifredefining
\csname label\the\loopnum\endcsname
\expandafter\gdef\csname topfloat\the\loopnum\endcsname{}\fi}
\vskip\intextfloatskip %%
\vskip-4pt %% probably an artifact of topskip??
}%
\else% table ==>
\expandafter\gdef\csname topfloat\the\figandtabnumber\endcsname{%
\vbox{\vskip\PushOneColTopTab %%
\csname caption\the\loopnum\endcsname
\csname letteredcaption\the\loopnum\endcsname
\csname continuedcaption\the\loopnum\endcsname
\csname letteredcontcaption\the\loopnum\endcsname
\vskip\captionskip
\unvbox\csname figandtabbox\the\loopnum\endcsname
\ifredefining
\csname label\the\loopnum\endcsname
\expandafter\gdef\csname topfloat\the\loopnum\endcsname{}\fi
}\vskip\intextfloatskip %% why don't we need this?
\vskip-10pt}
\fi\fi%
%
\else% bottom float
%
\ifcaptypefig
\expandafter\gdef\csname botfloat\the\figandtabnumber\endcsname{%
\vskip\intextfloatskip
\vbox{\unvbox\csname figandtabbox\the\loopnum\endcsname
\vskip\abovefigcaptionskip
\csname caption\the\loopnum\endcsname
\csname letteredcaption\the\loopnum\endcsname%
\csname continuedcaption\the\loopnum\endcsname%
\csname letteredcontcaption\the\loopnum\endcsname%
\vskip\PushOneColBotFig%%
\ifredefining%
\csname label\the\loopnum\endcsname
\expandafter\gdef\csname botfloat\the\loopnum\endcsname{}\fi}}%
\else
\ifcaptypeplate
\expandafter\gdef\csname botfloat\the\figandtabnumber\endcsname{%
\vskip\intextfloatskip
\vbox{\unvbox\csname figandtabbox\the\loopnum\endcsname
\vskip\abovefigcaptionskip
\csname caption\the\loopnum\endcsname
\csname letteredcaption\the\loopnum\endcsname%
\csname continuedcaption\the\loopnum\endcsname%
\csname letteredcontcaption\the\loopnum\endcsname%
\vskip\PushOneColBotFig%%
\ifredefining%
\csname label\the\loopnum\endcsname
\expandafter\gdef\csname botfloat\the\loopnum\endcsname{}\fi}}%
\else% TABLE
\expandafter\gdef\csname botfloat\the\figandtabnumber\endcsname{%
\vskip\intextfloatskip
\vbox{\csname caption\the\loopnum\endcsname
\csname letteredcaption\the\loopnum\endcsname
\csname continuedcaption\the\loopnum\endcsname
\csname letteredcontcaption\the\loopnum\endcsname%
\vskip.5\intextfloatskip
\unvbox\csname figandtabbox\the\loopnum\endcsname%
\vskip\PushOneColBotTab
\ifredefining%
\csname label\the\loopnum\endcsname
\expandafter\gdef\csname botfloat\the\loopnum\endcsname{}\fi}}%
\fi\fi\fi}
\makeatother
Best Answer
I deleted the markup that was causing warnings in the log, and the floats appear at the top of page 2 as you requested: