[Tex/LaTex] tikz node distance for particular set of nodes

nodestikz-pgf

I'd like to change the node distance for a specific set of nodes, e.g. the first two in "introduction". The distance for the nodes in a set should be smaller, while the distance in between the sets should be bigger to make sure the caption below it is well readable. It should apply for all sets and nodes in the picture. I'm not sure how I can change the node distance variable so that it applies only to a specific set. enter image description here

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{shapes.geometric, arrows, calc, fit, positioning, chains, arrows.meta}

%%% styles for Figure: Structure of the paper %%%
\tikzstyle{structure} = [rectangle, rounded corners, minimum width=5cm, minimum height=1cm,text centered, draw=black, fill=white!30]
\tikzstyle{arrow} = [thick,->,>=stealth]


\begin{document}

\begin{figure}
\centering
\begin{tikzpicture}[node distance=2cm]

\node (introduction) [structure] {Introduction to the topic};
\node (methodology) [structure, below of=introduction] {Problem definition, objectives, research methodology};
\node (theoretical) [structure, below of=methodology] {Theoretical considerations};
\node (model) [structure, below of=theoretical] {Definition of an integrated model of trust};
\node (interviews) [structure, below of=model] {Expert interviews};
\node (results) [structure, below of=interviews, text width=5cm] {Results};
\node (discussion) [structure, below of=results] {Discussion};

%arrows
\draw [arrow] (introduction) -- (methodology);
\draw [arrow] (methodology) -- (theoretical);
\draw [arrow] (theoretical) -- (model);
\draw [arrow] (model) -- (interviews);
\draw [arrow] (interviews) -- (results);
\draw [arrow] (results) -- (discussion);

%%% RECTANGLES %%%
\node[draw, thick, dotted, rounded corners, inner xsep=1em, inner ysep=1em, fit=(introduction) (methodology)] (box) {};
\node[fill=white] at (box.south) {Introduction};
\node[draw, thick, dotted, rounded corners, inner xsep=1em, inner ysep=1em, fit=(theoretical) (model) (interviews)] (box) {};
\node[fill=white] at (box.south) {Main part};
\node[draw, thick, dotted, rounded corners, inner xsep=1em, inner ysep=1em, fit=(results) (discussion)] (box) {};
\node[fill=white] at (box.south) {Conclusion};

\end{tikzpicture}
\caption{Structure of the paper} \label{fig:structure}
\end{figure}   

\end{document}

Best Answer

You can simply do it by adding <location> = x<your unit> of <node-name> instead of doing it statically like <location> of = <node-name>. As @marmot suggested, it is part of positioning package of tikz.

For instance:

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{shapes.geometric, arrows, calc, fit, positioning, chains, arrows.meta}

%%% styles for Figure: Structure of the paper %%%
\tikzstyle{structure} = [rectangle, rounded corners, minimum width=5cm, minimum height=1cm,text centered, draw=black, fill=white!30]
\tikzstyle{arrow} = [thick,->,>=stealth]


\begin{document}

\begin{figure}
\centering
\begin{tikzpicture}[node distance=2cm]

\node (introduction) [structure] {Introduction to the topic};
\node (methodology) [structure, below =0.5cm of introduction] {Problem definition, objectives, research methodology};
\node (theoretical) [structure, below =2cm of methodology] {Theoretical considerations};
\node (model) [structure, below of=theoretical] {Definition of an integrated model of trust};
\node (interviews) [structure, below of=model] {Expert interviews};
\node (results) [structure, below of=interviews, text width=5cm] {Results};
\node (discussion) [structure, below of=results] {Discussion};

%arrows
\draw [arrow] (introduction) -- (methodology);
\draw [arrow] (methodology) -- (theoretical);
\draw [arrow] (theoretical) -- (model);
\draw [arrow] (model) -- (interviews);
\draw [arrow] (interviews) -- (results);
\draw [arrow] (results) -- (discussion);

%%% RECTANGLES %%%
\node[draw, thick, dotted, rounded corners, inner xsep=1em, inner ysep=1em, fit=(introduction) (methodology)] (box) {};
\node[fill=white] at (box.south) {Introduction};
\node[draw, thick, dotted, rounded corners, inner xsep=1em, inner ysep=1em, fit=(theoretical) (model) (interviews)] (box) {};
\node[fill=white] at (box.south) {Main part};
\node[draw, thick, dotted, rounded corners, inner xsep=1em, inner ysep=1em, fit=(results) (discussion)] (box) {};
\node[fill=white] at (box.south) {Conclusion};

\end{tikzpicture}
\caption{Structure of the paper} \label{fig:structure}
\end{figure}   

\end{document}

will give you something like this (as similar to the space you requested in your question):

enter image description here

As per @marmot's suggestion: by using tikzset{...} instead of the depreciated tikzstyle{...} environment:

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{shapes.geometric, arrows, calc, fit, positioning, chains, arrows.meta}

%%% styles for Figure: Structure of the paper %%%

\tikzset{
    structure/.style = {draw, rectangle,
        minimum height=1cm,
        minimum width=5cm, rounded corners,, text centered, draw=black, fill=white!30},
    arrow/.style = {thick, ->, >=stealth}
}


\begin{document}

    \begin{figure}
        \centering
        \begin{tikzpicture}[node distance=2cm]

        \node (introduction) [structure] {Introduction to the topic};
        \node (methodology) [structure, below =0.5cm of introduction] {Problem definition, objectives, research methodology};
        \node (theoretical) [structure, below =2cm of methodology] {Theoretical considerations};
        \node (model) [structure, below of=theoretical] {Definition of an integrated model of trust};
        \node (interviews) [structure, below of=model] {Expert interviews};
        \node (results) [structure, below of=interviews, text width=5cm] {Results};
        \node (discussion) [structure, below of=results] {Discussion};

        %arrows
        \draw [arrow] (introduction) -- (methodology);
        \draw [arrow] (methodology) -- (theoretical);
        \draw [arrow] (theoretical) -- (model);
        \draw [arrow] (model) -- (interviews);
        \draw [arrow] (interviews) -- (results);
        \draw [arrow] (results) -- (discussion);

        %%% RECTANGLES %%%
        \node[draw, thick, dotted, rounded corners, inner xsep=1em, inner ysep=1em, fit=(introduction) (methodology)] (box) {};
        \node[fill=white] at (box.south) {Introduction};
        \node[draw, thick, dotted, rounded corners, inner xsep=1em, inner ysep=1em, fit=(theoretical) (model) (interviews)] (box) {};
        \node[fill=white] at (box.south) {Main part};
        \node[draw, thick, dotted, rounded corners, inner xsep=1em, inner ysep=1em, fit=(results) (discussion)] (box) {};
        \node[fill=white] at (box.south) {Conclusion};

        \end{tikzpicture}
        \caption{Structure of the paper} \label{fig:structure}
    \end{figure}   

\end{document}

We will get the same as before.

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