Dibujar flechas desde diferentes bordes del nodo/cuadro de decisión

Question

Soy nuevo en tikz y no entiendo cómo dibujar líneas que se originan desde todos los bordes de un cuadro de decisión hacia otros nodos.

En el siguiente diagrama , ¿cómo puedo especificar el punto de origen de una flecha? Por ejemplo, quiero dibujar una flecha desde la parte inferior de la Decisión 1 hasta el borde izquierdo de la Decisión 2, pero no sé cómo.

Mi código:

\documentclass{article}
\usepackage{tikz}
\usepackage{fixltx2e}
\usetikzlibrary{shapes,arrows}
\usetikzlibrary{positioning}
\usepackage[active,tightpage]{preview}
\PreviewEnvironment{tikzpicture}
\setlength\PreviewBorder{5pt}%
%%%>
\begin{document}
\pagestyle{empty}

% Define block styles
\tikzstyle{decision} = [diamond, draw, fill=blue!20, 
    text width=6.5em, text badly centered, node distance=3cm, inner sep=0pt]
\tikzstyle{block} = [rectangle, draw, fill=blue!20, 
    text width=10em, text centered, rounded corners, minimum height=4em]
\tikzstyle{mycircle} = [circle, thick, draw=orange, minimum height=4mm]

\tikzstyle{line} = [draw, -latex']
\tikzstyle{cloud} = [draw, ellipse,fill=red!20, node distance=3cm,
    minimum height=2em]

\begin{tikzpicture}[align=center,node distance = 2cm, auto]
    % Place nodes
    \node [block] (init) {Read system data};
    \node [block, right of=init, node distance=6cm] (trip) {Trip};

    \node [block, below of=init, node distance=2.7cm] (setloadavg)
             {Set average loading level to L\textsubscript{avg}=[0.8,0.9,1,1.1]};
    \node [decision, right of=setloadavg, node distance=6cm] (decision2) {Decision2};
    \node [block, right of=decision2, node distance=3cm] (stop1) {Stop};

    \node [block, below of=setloadavg, node distance=3cm] (setk) {Set K};
    \node [decision, right of=setk, node distance=6cm] (decision3) {Decision3};
    \node [mycircle, right of=decision3, node distance=4cm] (circle1) {1};

    \node [block, below of=setk, node distance=2cm] (startsim)
        {Start simulation (run 1) to generate cascade data, K=0};
    \node [block, right of=startsim, node distance=6cm] (increment) {Increment};
    \node [mycircle, left of=startsim, node distance=4cm] (circle2) {2};

    \node [block, below of=startsim, node distance=3cm] (setloadlevel) {Set Load level};
    \node [decision, right of=setloadlevel, node distance=6cm] (decision4) {Decision4};
    \node [mycircle, right of=decision4, node distance=4cm] (circle3) {2};

    \node [block, below of=setloadlevel, node distance=3cm] (runloadflow) {Run load flow};
    \node [block, right of=runloadflow, node distance=6cm] (stop2) {stop};

    \node [decision, below of=runloadflow, node distance=3cm] (decision1) {Decision1};
    \node [mycircle, left of=decision1, node distance=4cm] (circle2) {1};


    % Draw edges
    \path [line] (init) -- (setloadavg);
    \path [line] (setloadavg) -- (setk);
    \path [line] (setk) -- (startsim);
    \path [line] (startsim) -- (setloadlevel);
    %\path [line] (startsim) -- (circle2);
    \path [line] (setloadlevel) -- (runloadflow);
    \path [line] (runloadflow) -- (decision1);
    \path [line] (decision1) -- node [near start] {Yes} +(3,0) |-  (trip);


\end{tikzpicture}
\end{document}

Agradecería alguna explicación de la solución y sugerencias de documentación, si es posible.

Gracias

Answer 1

Una posibilidad:

\documentclass{article}
\usepackage{tikz}
\usepackage{fixltx2e}
\usetikzlibrary{shapes,arrows}
\usetikzlibrary{positioning}
\usepackage[active,tightpage]{preview}
\PreviewEnvironment{tikzpicture}
\setlength\PreviewBorder{5pt}%
%%%>
\begin{document}
\pagestyle{empty}

% Define block styles
\tikzstyle{decision} = [diamond, draw, fill=blue!20,
    text width=6.5em, text badly centered, node distance=3cm, inner sep=0pt]
\tikzstyle{block} = [rectangle, draw, fill=blue!20,
    text width=10em, text centered, rounded corners, minimum height=4em]
\tikzstyle{mycircle} = [circle, thick, draw=orange, minimum height=4mm]

\tikzstyle{line} = [draw, -latex']
\tikzstyle{cloud} = [draw, ellipse,fill=red!20, node distance=3cm,
    minimum height=2em]

\begin{tikzpicture}[align=center,node distance = 2cm, auto]
    % Place nodes
    \node [block] (init) {Read system data};
    \node [block, right of=init, node distance=6cm] (trip) {Trip};

    \node [block, below of=init, node distance=2.7cm] (setloadavg)
             {Set average loading level to L\textsubscript{avg}=[0.8,0.9,1,1.1]};
    \node [decision, right of=setloadavg, node distance=6cm] (decision2) {Decision2};
    \node [block, right of=decision2, node distance=3cm] (stop1) {Stop};

    \node [block, below of=setloadavg, node distance=3cm] (setk) {Set K};
    \node [decision, right of=setk, node distance=6cm] (decision3) {Decision3};
    \node [mycircle, right of=decision3, node distance=4cm] (circle1) {1};

    \node [block, below of=setk, node distance=2cm] (startsim)
        {Start simulation (run 1) to generate cascade data, K=0};
    \node [block, right of=startsim, node distance=6cm] (increment) {Increment};
    \node [mycircle, left of=startsim, node distance=4cm] (circle2) {2};

    \node [block, below of=startsim, node distance=3cm] (setloadlevel) {Set Load level};
    \node [decision, right of=setloadlevel, node distance=6cm] (decision4) {Decision4};
    \node [mycircle, right of=decision4, node distance=4cm] (circle3) {2};

    \node [block, below of=setloadlevel, node distance=3cm] (runloadflow) {Run load flow};
    \node [block, right of=runloadflow, node distance=6cm] (stop2) {stop};

    \node [decision, below of=runloadflow, node distance=3cm] (decision1) {Decision1};
    \node [mycircle, left of=decision1, node distance=4cm] (circle2) {1};


    % Draw edges
    \path [line] (init) -- (setloadavg);
    \path [line] (setloadavg) -- (setk);
    \path [line] (setk) -- (startsim);
    \path [line] (startsim) -- (setloadlevel);
    %\path [line] (startsim) -- (circle2);
    \path [line] (setloadlevel) -- (runloadflow);
    \path [line] (runloadflow) -- (decision1);
    \path [line] (decision1) -- node [near start] {Yes} +(3,0) coordinate (my coord) |-  (trip);
    \path [line] (decision1.south) -- +(0,-20pt) -| ([xshift=5pt, yshift=-5pt]my coord) |- (decision2.west);


\end{tikzpicture}
\end{document}

Al colocar una coordenada en la línea anterior, podemos navegar alrededor de ella al colocar la ruta de la nueva flecha. .southy .westson anclajes de los nodos decision1y decision2, correspondientes al punto de entrada y salida que desee. Utilizar el xshift...,yshift...asegura que la línea se acerque a la anterior, sin quedar justo encima de ella.

Tenga en cuenta que parte de su sintaxis está desactualizada. Por ejemplo, deberías utilizar \tikzseten lugar de \tikzstyle.