The distance issue between nodes in tikz

Question

I am trying to place two nodes in the northeast and and northwest of another node. However, I am facing a visual issue.

Here is the example that I am working on.

\documentclass{standalone}
\usepackage{tikz}
\usetikzlibrary{shapes,arrows,positioning}
\begin{document}


\tikzstyle{block} = [rectangle, draw, fill=white!20,  node distance=3cm,
    text width=6em, text centered, rounded corners, minimum height=3em]
\tikzstyle{line} = [draw, very thick, color=black!50, -latex']


\begin{tikzpicture}[scale=2,node distance = 2cm, auto]
    \node [block] (A) {Initial step};
    \node [block, right =of A] (B) {The next step};

    \begin{scope}[node distance=4cm and 5cm]
        \node [block, right = of B, anchor = south east] (C) {The third step};
        \node [block, right = of B, , anchor = north east ] (D) {The fourth step};
    \end{scope}

    \path [line] (A) -- (B);
    \path [line] (B) -- (C);
    \path [line] (B) -- (D);
\end{tikzpicture}
\end{document}

The first issue is that as you can see I have different horizontal distances between nodes. The second problem is that I am not able to add vertical distance between nodes as shown in the image.

Answer 1

As suplement to @farahfeza answer:

• I would define node distance only once:
  • uniform distance in diagram,
  • shorter code
• Use of tikzstyle is deprecated, instead it you should use \tikset or define styles in `tikzpicture options (as is done in MWE below)
• Also library arrows is deprecated. Instead it is better to use more powerful arrows.meta

\documentclass[margin=3.141592]{standalone}
\usepackage{tikz}
\usetikzlibrary{arrows.meta,
                positioning,
                shapes}
                
\begin{document}
    \begin{tikzpicture}[
 node distance = 5mm and 22mm, 
  block/.style = {draw, rounded corners, fill=#1,
                  minimum height=3em, text width=6em, align=center},
block/.default = white,
every edge/.append style = {draw=black!50, thick, -Latex}
                    ]
\node [block] (A) {Initial step};
\node [block, right =of A] (B) {The next step};
\node [block, above right = of B] (C) {The third step};
\node [block, below right = of B] (D) {The fourth step};
%
\path   (A) edge (B)
        (B.+5) edge (C.west) 
        (B.-5) edge (D.west);
    \end{tikzpicture}
\end{document}

Answer 2

You can specify the relative x and y positions separately using the tikz library positioning, like this.

\documentclass[margin=3mm]{standalone}
\usepackage{tikz}
\usetikzlibrary{shapes,arrows,positioning}
\begin{document}

\tikzstyle{block} = [rectangle, draw, fill=white!20,  node distance=3cm,
    text width=6em, text centered, rounded corners, minimum height=3em]
\tikzstyle{line} = [draw, very thick, color=black!50, -latex']


\begin{tikzpicture}[scale=2,node distance = 2cm, auto]
    \node [block] (A) {Initial step};
    \node [block, right =of A] (B) {The next step};

    \begin{scope}[node distance=4cm and 5cm]
        \node [block, above right= 1cm and 4cm of B, anchor = south east] (C) {The third step};
        \node [block, below right= 1cm and 4cm of B,  anchor = north east] (D) {The fourth step};
    \end{scope}

    \path [line] (A) -- (B);
    \path [line] (B.10) -- (C.180);
    \path [line] (B.-10) -- (D.180);
\end{tikzpicture}
\end{document}