Posicionando setas tikz em coordenadas dentro de tabulares

Question

Preciso criar um slide com várias tabelas e usar a seta para apontar para os elementos dentro dessas tabelas.

No entanto, estou tendo problemas para especificar onde as tabelas, textos e setas devem aparecer. Como posso fazer isso?

Meu exemplo mínimo não funcional segue:

\documentclass{beamer}              % only frames
\usepackage{tikz}
\usetikzlibrary{shapes.geometric,positioning,matrix}
\newcommand{\tikzmark}[1]{\tikz[remember picture] \node[coordinate] (#1) {#1};}

\begin{document}
\begin{frame}\frametitle{Example}
  \begin{tabular}{ccccc}
\tikzmark{col1}
      \begin{tabular}{|c|}\hline
          \tikzmark{elem1}2\\\hline
          3\\\hline
          7\\\hline
          6\\\hline
          1\\\hline                                                                                                                               
          5\\\hline
          4\\\hline
      \end{tabular}&
\tikzmark{col2}
      \begin{tabular}{|c|}\hline
          \tikzmark{elem2}4\\\hline
          2\\\hline
          1\\\hline
          3\\\hline
          6\\\hline
          7\\\hline
          5\\\hline
      \end{tabular}&
\tikzmark{mat}
    \begin{tabular}{|c|c|c|c|}\hline
1&0&1&0\\\hline
1&0&0&1\\\hline
0&1&0&1\\\hline
0&1&0&1\\\hline
0&1&0&1\\\hline
1&0&1&0\\\hline
1&0&1&0\\\hline
    \end{tabular}&
\tikzmark{sigMat}
\begin{tabular}{|c|c|c|c|}\hline
\tikzmark{elem3}2&1&2&1\\\hline
2&1&4&1\\\hline                                                                                                                                   
1&2&1&2\\\hline
  \end{tabular}
\end{tabular}
 \begin{tikzpicture}[remember picture]
\node [above=.01cm of col2] {\tiny Text Above columns};
\node[above=.01cm of mat] {\tiny Above 1st matrix};
\node[above=.1cm of sigMat]{\tiny Above 2nd matrix};

\node[above=2cm of mat,text width=6cm] (txt1) {Arrows go from here to...};

\path[draw,->] (txt1.south west) -- node {goes to 1st elem} (elem1);
\path[draw,->] (txt1.south) -- node {goes to 2nd elem} (elem2);
\path[draw,->] (txt1.south east) -- node {goes to 3rd elem} (elem3);
  \end{tikzpicture}
\end{frame}                                                                                                                                       

\end{document}

Isso resulta no seguinte slide:

Answer 1

O principal problema é que você esqueceu overlayno seu arquivo tikzpicture. Porém, isso também serve para informar que existe a tikzmarkbiblioteca, com a qual você pode fazer os nós das tabelas e os subnós dos elementos.

\documentclass{beamer}              % only frames
\usepackage{tikz}
\usetikzlibrary{shapes.geometric,positioning,matrix,fit,tikzmark}

\begin{document}
\begin{frame}
\frametitle{Example}
\begin{tabular}{ccccc}
\tikzmarknode{col1}{\begin{tabular}{|c|}\hline
          \subnode{elem1}{2}\\\hline
          3\\\hline
          7\\\hline
          6\\\hline
          1\\\hline                                                                                                                               
          5\\\hline
          4\\\hline
      \end{tabular}}&
\tikzmarknode{col2}{\begin{tabular}{|c|}\hline
          \subnode{elem2}{4}\\\hline
          2\\\hline
          1\\\hline
          3\\\hline
          6\\\hline
          7\\\hline
          5\\\hline
      \end{tabular}}&
\tikzmarknode{col3}{\begin{tabular}{|c|c|c|c|}\hline
1&0&1&0\\\hline
1&0&0&1\\\hline
0&1&0&1\\\hline
0&1&0&1\\\hline
0&1&0&1\\\hline
1&0&1&0\\\hline
1&0&1&0\\\hline
    \end{tabular}}&
\tikzmarknode{sigMat}{\begin{tabular}{|c|c|c|c|}\hline
\subnode{elem3}{2}&1&2&1\\\hline
2&1&4&1\\\hline                                                                                                                                   
1&2&1&2\\\hline
  \end{tabular}}
\end{tabular}
\begin{tikzpicture}[remember picture,overlay]
 \node[fit=(col1)(col2)(col3)](cols){};
 \node[above=.01cm of cols,font=\tiny] {Text Above columns};
 \node[above=.01cm of col1,font=\tiny] {Above 1st matrix};
 \node[above=.1cm of sigMat,font=\tiny]{Above 2nd matrix};
% 
 \node[above=1cm of cols.north east] (txt1) {Arrows go from here to\dots};
% 
 \path[draw,->] (txt1.south west) -- node[sloped,font=\tiny,above] {goes to 1st elem} (elem1);
 \path[draw,->] (txt1.south) -- node[sloped,font=\tiny,above] {goes to 2nd elem} (elem2);
 \path[draw,->] (txt1.south east) -- node[sloped,font=\tiny,above] {goes to 3rd elem} (elem3);
\end{tikzpicture}
\end{frame}
\end{document}