Vrftjkry

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.

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}

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):

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.

You can define two styles with different node distance.

tikzset{nearnodes/.style={node distance=0.5cm,}}

tikzset{farnodes/.style={node distance=1cm,}

Then use these styles for the corresponding nodes.

documentclass{article}

usepackage{tikz}

usetikzlibrary{shapes.geometric, arrows, calc, fit, positioning, chains, arrows.meta}



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

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

tikzset{arrow/.style = {thick,->,>=stealth,}}

tikzset{nearnodes/.style={node distance=0.5cm,}}

tikzset{farnodes/.style={node distance=2cm}}



begin{document}



begin{figure}

centering

begin{tikzpicture}

node[nearnodes] (introduction) [structure] {Introduction to the topic};

node[nearnodes] (methodology) [structure, below =of introduction] {Problem definition, objectives, research methodology};

node[farnodes] (theoretical) [structure, below =of methodology] {Theoretical considerations};

node[nearnodes] (model) [structure, below =of theoretical] {Definition of an integrated model of trust};

node[nearnodes] (interviews) [structure, below =of model] {Expert interviews};

node[farnodes] (results) [structure, below =of interviews, text width=5cm] {Results};

node[nearnodes] (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}

i would redesign your flowchart as follows:

in the mwe the use of the positioning library is consistent, with use of the chains library the nodes are named by chain name and connecting lines are defined by macro ˙join`. with this the code is (far) more concise that in other answers. labels of the article parts are defined with node labels:

documentclass{article}

usepackage{tikz}

usetikzlibrary{arrows.meta,

                chains,

                fit,

                positioning}



begin{document}



begin{figure}

centering

begin{tikzpicture}[

   node distance = 4mm,

     start chain = A going below,   % <--- chain name is A

      arr/.style = {thick, -Stealth},

structure/.style = {rectangle, draw, rounded corners,

                    text width=48mm, inner sep=2mm, align=flush center,

                    on chain=A, join=by arr},

every label/.append style = {fill=white, font=footnotesize, inner ysep=1pt}

                    ]

    begin{scope}[every node/.append style={structure}]

node   {Introduction to the topic};        % A-1: first name

node   {Problem definition, objectives, research methodology};

node [below=11mm of A-2] % <--- increased distance between 

                          % adjacent nodes

        {Theoretical considerations};

node   {Definition of an integrated model of trust};

node   {Expert interviews};

node [below=11mm of A-5] % <--- increased distance between 

                          % adjacent nodes

        {Results};

node   {Discussion};                       % A-7: last node name

    end{scope}

%%% RECTANGLES %%%

    begin{scope}[every node/.append style={draw, rounded corners, densely dotted,

                                            inner sep=3mm}]

node   [label={[anchor=center]south:Introduction},

         fit=(A-1) (A-2)]        {};

node   [label={[anchor=center]below:Main Part},

         fit=(A-3) (A-5)]        {};

node   [label={[anchor=center]below:Conclusion},

         fit=(A-6) (A-7)]       {};

    end{scope}

end{tikzpicture}

    caption{Structure of the paper} label{fig:structure}

end{figure}

end{document}