title: Latex flowchart line crossing line
body: <p>I am building a flowchart which looks almost as I want it. The last detail that I would like to modify concerns 2 lines crossing one another.</p>
  
  <p>Here is my code:</p>
  
  <pre><code>\tikzstyle{block1}    = [rectangle, rounded corners,  minimum width=3cm, minimum height=1cm, text centered, draw, fill=blue!20, text width=6cm]
  \tikzstyle{block2}    = [rectangle, rounded corners,  minimum width=3cm, minimum height=1cm, text centered, draw, fill=blue!20, text width=3cm]
  \tikzstyle{decision}  = [diamond, minimum width=3cm, minimum height=1cm, text centered, draw, fill=blue!20, text width=2cm] % node distance=3cm, inner sep=0pt
  \tikzstyle{line}      = [draw, -latex']
  
  \begin{figure}[ht]
      \begin{center}
          \begin{tikzpicture}[node distance = 2cm, auto]
          % Place nodes
              \node [block1] (1) {\textbf{\small Study of basic factors}\\    \footnotesize Plant characteristics, mechanisms of nuclide production and waste streams};
              \node [block1, below of=1, node distance=1.8cm]  (2)  {\textbf{\small Development of sampling plan}};
              \node [block1, below of=2, node distance=1.7cm]  (3)  {\textbf{\small Sampling and analysis}};
              \node [block1, below of=3, node distance=2cm]  (4)  {\textbf{\small Observation and evaluation of nuclide activity database}\\  \footnotesize Selecting key nuclide and verifying correlation between DTM nuclides and KN};
              \node [decision, below of=4, node distance=3.2cm]  (5)  {\textbf{\small Applicability of SF method}};
              \node [block2, right of=5, node distance=4cm] (6)  {\textbf{\small Other methods}\\ \footnotesize Mean activity, ...};
              \node [block2, left of=5, node distance=4cm]  (7)  {\textbf{\small Applying statistics}};
              \node [block2, below of=5, node distance=3.5cm] (8) {\textbf{\small SF classifications}\\ \footnotesize Unification and classification of groups};
              \node [block2, left of=8, node distance=4cm] (9) {\textbf{\small Reference}};
              \node [block2, below of=8, node distance=2cm] (10) {\textbf{Determination of SF}};
              \node [block2, left of=10, node distance=4cm] (11) {\textbf{Applying statistics}};
              \node [block2, right of=10, node distance=4cm] (12) {\textbf{Assess KN activity}\\ Dose rate and $\gamma$-spectra};
              \node [decision, below of=10, node distance=2.5cm] (13) {\textbf{Calculation}};
              \node [block1, below of=13, node distance=2.5cm] (14) {\textbf{Determining the activity of DTM}};
  
          % Draw edges
              \path [line] (1) -- (2);
              \path [line] (2) -- (3);
              \path [line] (3) -- (4);
              \path [line] (4) -- (5);
              \path [line] (4) -| ([xshift=1cm, yshift=0cm]6.east) |- (12);
              \path [line] (7) -- (5);
              \path [line] (5) -- (6);
              \path [line] (6) -| ([xshift=2cm, yshift=0cm]6.east) |-(14);
              \path [line] (5) -- (8);
              \path [line] (9) -- (8);
              \path [line] (8) -- (10);
              \path [line] (11) -- (10);
              \path [line] (10) -- (13);
              \path [line] (12) |- (13);
              \path [line] (13) -- (14);
          \end{tikzpicture}
          \caption{Complete characterization process \cite{iso21238}.}
          \label{fig_1.1}
      \end{center}
  \end{figure}
  </code></pre>
  
  <p>and here you can find how it looks like:</p>
  
  <p><img src="https://i.stack.imgur.com/S6DQm.png" alt="flowchart"></p>
  
  <p>What I want is to add an arc in order to avoid 2 lines crossing each other; in particular I would like one arc in the line going from the block "other methods" to the block "determining the activity of DTM".</p>
  
  <p>Thanks a lot for your help.</p>
  
  <p>Cheers,</p>
  
  <p>Biagio</p>