Arrows along path in TikZ flowchart

Question

Instead of drawing each arrow separately, I am interested in a quicker way to draw arrows along a path in a flowchart.

Let's look at some code first, MWE:

\documentclass{article}

\usepackage[svgnames]{xcolor}
\usepackage{pgf,tikz}
\usetikzlibrary{chains,positioning,arrows,shapes.geometric,quotes,fit,calc}

\tikzstyle{startstop} = [%
rectangle,
rounded corners,
%   minimum width=3cm,
%   max width=2cm,
minimum height=1cm,
text centered,
text width=2cm,
line width=1pt,
draw=DarkBlue,
fill=DarkBlue!30
]

\tikzstyle{process} = [%
rectangle,
%   minimum width=3cm,
%   max width=2cm,
minimum height=1cm,
text centered,
text width=2cm,
draw=orange,
fill=orange!30
]

\tikzstyle{arrow} = [%
thick,
->,
>=stealth,
]

\tikzstyle{mainarrow} = [%
ultra thick,
->,
>=stealth,
]

\begin{document}

    \begin{tikzpicture}
    \node (mycenternode) [startstop]                      {Isgrind};
    \node (mynorthnode)  [process, above=of mycenternode] {Sami};
    \node (mysouthnode)  [process, below=of mycenternode] {Romrike};
    \node (mywestnode)   [process, left=of mycenternode]  {Rykinmaa};
    \node (myeastnode)   [process, right=of mycenternode] {Lukinsola};

    \draw [mainarrow] (mynorthnode)  --                           (mycenternode);
    \draw [mainarrow] (mycenternode) -- node[anchor=west]  {kuf}  (mysouthnode);
    \draw [arrow] (mywestnode)   -- node[anchor=south] {ders} (mycenternode);
    \draw [arrow] (mycenternode)  -- node[anchor=south]  {olan} (myeastnode);

    \path [arrow] (mywestnode) |- node[anchor=south] {punrot} (mynorthnode) -| (myeastnode);
    \end{tikzpicture}

\end{document}

Instead of having to say

    \draw [mainarrow] (mynorthnode)  -- (mycenternode);
    \draw [mainarrow] (mycenternode) -- node[anchor=west]  {kuf}  (mysouthnode);
    \draw [arrow] (mywestnode) -- node[anchor=south] {ders} (mycenternode);
    \draw [arrow] (mycenternode) -- node[anchor=south]  {olan} (myeastnode);

I wonder how to shorten that to something like

\path [mainarrow] (mynorthnode)  -- (mycenternode) -- node[anchor=west]  {kuf}  (mysouthnode);
\path [arrow] (mywestnode) -- node[anchor=south] {ders} (mycenternode) -- node[anchor=south]  {olan} (myeastnode);

EXTRA: In the last few lines, you can discern a \path. I don't really understand why it's not drawing anything.

Answer 1

I think you are looking for the edge operation. You were already loading quotes (and several packages that you do not use), which allows you to attach the labels to the arrows with a shorter syntax. The relevant piece of your code can thus be condensed to

\draw  (mynorthnode)  edge[mainarrow]  (mycenternode) 
    (mycenternode) edge[mainarrow,"kuf"]    (mysouthnode)
     (mywestnode)   edge[arrow,"ders"] (mycenternode)
  (mycenternode)  edge[arrow,"olan"] (myeastnode);

Note that \path alone does not draw. This is the reason why the lines do not appear. I added two styles for edges with corners, BR and BL, such that the path in the end can be drawn with edges as well,

\draw [arrow] (mywestnode)  edge[BR,"punrot"] (mynorthnode)
 (mynorthnode) edge[BL] (myeastnode);

This is the MWE with some unused libraries removed and \tikzset instead of \tikzstyle.

\documentclass{article}

\usepackage[svgnames]{xcolor}
\usepackage{pgf,tikz}
\usetikzlibrary{positioning,quotes}

\tikzset{startstop/.style={
rectangle,
rounded corners,
%   minimum width=3cm,
%   max width=2cm,
minimum height=1cm,
text centered,
text width=2cm,
line width=1pt,
draw=DarkBlue,
fill=DarkBlue!30},
process/.style={%
rectangle,
%   minimum width=3cm,
%   max width=2cm,
minimum height=1cm,
text centered,
text width=2cm,
draw=orange,
fill=orange!30},
arrow/.style={%
thick,
->,
>=stealth,
},
mainarrow/.style={%
ultra thick,
->,
>=stealth,
},
BR/.style={ to path={|- (\tikztotarget)  \tikztonodes}},
BL/.style={ to path={-| (\tikztotarget)  \tikztonodes}}}

\begin{document}

\begin{tikzpicture}
    \node (mycenternode) [startstop]                      {Isgrind};
    \node (mynorthnode)  [process, above=of mycenternode] {Sami};
    \node (mysouthnode)  [process, below=of mycenternode] {Romrike};
    \node (mywestnode)   [process, left=of mycenternode]  {Rykinmaa};
    \node (myeastnode)   [process, right=of mycenternode] {Lukinsola};

    \draw  (mynorthnode)  edge[mainarrow]  (mycenternode) 
        (mycenternode) edge[mainarrow,"kuf"]    (mysouthnode)
         (mywestnode)   edge[arrow,"ders"] (mycenternode)
      (mycenternode)  edge[arrow,"olan"] (myeastnode);

    \draw [arrow] (mywestnode)  edge[BR,"punrot"] (mynorthnode)
     (mynorthnode) edge[BL] (myeastnode);
\end{tikzpicture}
\end{document}

Answer 2

You will only get one arrow tip when you use --, but if you use edge instead, you'll get an arrow tip for each segment, as edge inserts a separate path (I think). Anyways, you can actually make do with specifying the center node only once:

\path [mainarrow]  (mycenternode) edge[<-]                          (mynorthnode)
                                  edge           node[right] {kuf}  (mysouthnode)
                                  edge[arrow,<-] node[above] {ders} (mywestnode)
                                  edge[arrow]    node[above] {olan} (myeastnode);