How to modify TikZ patterns

Question

The Task: Draw a ground for a tank.

My solution: Using TikZ patterns library (see page 171 of the TikZ & PGF manual).

MWE:

\documentclass{scrartcl}
\usepackage{stanli}% loads TikZ, see: https://ctan.org/pkg/stanli

\usetikzlibrary{patterns}

\begin{document}

  \begin{tikzpicture}

    % ground
    \draw
      [very thick] (0, 0) -- (5, 0);
    % for comparison
    \support{3}{0, 0};% stanli
    \filldraw         % tikz
      [pattern = north east lines] (1, 0) rectangle (5, -.4);
    % tank
    \draw
      (5, 0)     .. controls (5, 1) and (5.1, 1.1)
                 .. (5.5, 1.1)
      (5.5, 1.4) .. controls (5.1, 1.4) and (5, 1.5)
                 .. (5, 2.5) -- (5, 5)
      (5, 4) -- (0, 4)
      (0, 5) -- (0, 0);
    % atmospheric pressure
    \node at (6, 5) {$p_0$};
    % density
    \node at (1, 3) {$\varrho$};
    % inflow
    \draw
      [->] (-.5, 5.5) .. controls (-.25, 5.5) and (.25, 5.5)
                      .. node[sloped, above] {Zufluss}
           (.5, 4.25);
    % hydrostatic head
    \draw
      (4, 4) -- (4.15, 4.3) -- (3.85, 4.3) -- cycle
      (3.85, 3.9) -- (4.15, 3.9)
      (3.90, 3.8) -- (4.10, 3.8)
      (3.95, 3.7) -- (4.05, 3.7);
    % velocity
    % v_1
    \draw
      [->] (2.5,4) node[above] {1} -- node[sloped, above, at end] {$v_1$} (2.5, 3);
    %v_2
    \draw
      [->] (5.5, 1.25) node[above = 5pt] {2} -- node[above, at end] {$v_2$} (6.5, 1.25);
    % flow line
    \draw
      [dashed] (2.5, 2.9) .. controls (3, 2) and (5, 1.25)
                          .. (5.4, 1.25);
    % coordinate system
    \support{3}{7.5, 1.25};
    \draw
      [->,dashed] (7, 1.25) -- node[sloped, above, at end] {$z$} (7, 2.5);
    % height
    \dimensioning{2}{8, 1.25}{8, 4}{8}[$h$];

  \end{tikzpicture}

\end{document}

The result: Right is the ground drawn by Tikz. That isn't nice (my opinion). Can I somehow modify the north east lines pattern, so that the ground for the tank looks like a ground drawn by the stanli package (for example \support{3}{coordinates}). The ground comes with the stanli package, if observe strictly, isn't a ground, but I like it and would use it here, but it has fixed length.

An completely different solution, which gives the same result for the ground like done by the stanli package (even with different length) is welcome too. Any suggestions?

P. S. Any other optimizations or criticism are welcome too!

Thank you for your help and effort in advance!

Answer 1

All I did was to copy the flexible hatch pattern from this answer and to adjust two parameters.

\documentclass{scrartcl}
\usepackage{stanli}% loads TikZ, see: https://ctan.org/pkg/stanli

\usetikzlibrary{patterns}
% from https://tex.stackexchange.com/a/29367/121799
\tikzset{
    hatch distance/.store in=\hatchdistance,
    hatch distance=10pt,
    hatch thickness/.store in=\hatchthickness,
    hatch thickness=2pt
}

\makeatletter
\pgfdeclarepatternformonly[\hatchdistance,\hatchthickness]{flexible hatch}
{\pgfqpoint{0pt}{0pt}}
{\pgfqpoint{\hatchdistance}{\hatchdistance}}
{\pgfpoint{\hatchdistance-1pt}{\hatchdistance-1pt}}%
{
    \pgfsetcolor{\tikz@pattern@color}
    \pgfsetlinewidth{\hatchthickness}
    \pgfpathmoveto{\pgfqpoint{0pt}{0pt}}
    \pgfpathlineto{\pgfqpoint{\hatchdistance}{\hatchdistance}}
    \pgfusepath{stroke}
}
\makeatother


\begin{document}

  \begin{tikzpicture}

    % ground
    \draw
      [very thick] (0, 0) -- (5, 0);
    % for comparison
    \support{3}{0, 0};% stanli
    \filldraw         % tikz
      [pattern=flexible hatch,
        hatch distance=5pt,
        hatch thickness=0.3pt] (1, 0) rectangle (5, -.4);
    % tank
    \draw
      (5, 0)     .. controls (5, 1) and (5.1, 1.1)
                 .. (5.5, 1.1)
      (5.5, 1.4) .. controls (5.1, 1.4) and (5, 1.5)
                 .. (5, 2.5) -- (5, 5)
      (5, 4) -- (0, 4)
      (0, 5) -- (0, 0);
    % atmospheric pressure
    \node at (6, 5) {$p_0$};
    % density
    \node at (1, 3) {$\varrho$};
    % inflow
    \draw
      [->] (-.5, 5.5) .. controls (-.25, 5.5) and (.25, 5.5)
                      .. node[sloped, above] {Zufluss}
           (.5, 4.25);
    % hydrostatic head
    \draw
      (4, 4) -- (4.15, 4.3) -- (3.85, 4.3) -- cycle
      (3.85, 3.9) -- (4.15, 3.9)
      (3.90, 3.8) -- (4.10, 3.8)
      (3.95, 3.7) -- (4.05, 3.7);
    % velocity
    % v_1
    \draw
      [->] (2.5,4) node[above] {1} -- node[sloped, above, at end] {$v_1$} (2.5, 3);
    %v_2
    \draw
      [->] (5.5, 1.25) node[above = 5pt] {2} -- node[above, at end] {$v_2$} (6.5, 1.25);
    % flow line
    \draw
      [dashed] (2.5, 2.9) .. controls (3, 2) and (5, 1.25)
                          .. (5.4, 1.25);
    % coordinate system
    \support{3}{7.5, 1.25};
    \draw
      [->,dashed] (7, 1.25) -- node[sloped, above, at end] {$z$} (7, 2.5);
    % height
    \dimensioning{2}{8, 1.25}{8, 4}{8}[$h$];

  \end{tikzpicture}

\end{document}

To an ordinary marmot's eye they are almost indistinguishable. Notice that at lower zoom the pattern does indeed look a bit weird on preview and even on acroread, but as @dexteritas points out, these are viewer issues that go away once one zooms in.