LaTeX | TikZ | Spider Web | How to visualize decimal numbers without rounding?

Question

I am currently "modelling" a spider web diagram. I need to visualize decimal numbers like 8.95. On the internet, I have found a very good solution to model a spider web diagram. Unfortunately, all decimal numbers will be rounded which gives a wrong visualization result in the diagram.

I tried two things with no success:

• Increased the scale from 0-15 (value 8.95) to 0-1500 (value 895)
• \begin{tikzpicture}[scale=1,x=15.0,y=15.0]

Does anyone know, how to allow decimal numbers in the spider web? Thanks a lot in advance!

Here a MWE:

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Spiderweb Diagram
%
% Author: Dominik Renzel
% Date; 2009-11-11
\documentclass{article}
%%%<
\usepackage{verbatim}
\usepackage[active,tightpage,floats]{preview}
\setlength\PreviewBorder{5pt}%
%%%>

\usepackage{tikz}
\usetikzlibrary{shapes}

\begin{document}

\newcommand{\D}{7} % number of dimensions (config option)
\newcommand{\U}{7} % number of scale units (config option)

\newdimen\R % maximal diagram radius (config option)
\R=3.5cm 
\newdimen\L % radius to put dimension labels (config option)
\L=4cm

\newcommand{\A}{360/\D} % calculated angle between dimension axes  

\begin{figure}[htbp]
 \centering

\begin{tikzpicture}[scale=1]
  \path (0:0cm) coordinate (O); % define coordinate for origin

  % draw the spiderweb
  \foreach \X in {1,...,\D}{
    \draw (\X*\A:0) -- (\X*\A:\R);
  }

  \foreach \Y in {0,...,\U}{
    \foreach \X in {1,...,\D}{
      \path (\X*\A:\Y*\R/\U) coordinate (D\X-\Y);
      \fill (D\X-\Y) circle (1pt);
    }
    \draw [opacity=0.3] (0:\Y*\R/\U) \foreach \X in {1,...,\D}{
        -- (\X*\A:\Y*\R/\U)
    } -- cycle;
  }

  % define labels for each dimension axis (names config option)
  \path (1*\A:\L) node (L1) {\tiny Security};
  \path (2*\A:\L) node (L2) {\tiny Content Quality};
  \path (3*\A:\L) node (L3) {\tiny Performance};
  \path (4*\A:\L) node (L4) {\tiny Stability};
  \path (5*\A:\L) node (L5) {\tiny Usability};
  \path (6*\A:\L) node (L6) {\tiny Generality};
  \path (7*\A:\L) node (L7) {\tiny Popularity};

  % Example Case (blue)
  \draw [color=blue,line width=1.5pt,opacity=0.5]
    (D1-1.5) --
    (D2-6.5) --
    (D3-4.2) --
    (D4-4.8) --
    (D5-3.6) --
    (D6-5.1) --
    (D7-2.3) -- cycle;

\end{tikzpicture}
\caption{Spiderweb Diagram (\D~Dimensions, \U-Notch Scale, 3 Samples)}
\label{fig:spiderweb}
\end{figure}

\end{document}

Answer 1

You can achieve what you want by "mixing" nodes using the calc library. I added 3 examples to you snippet, two in which the node is set right in the middle between two, and one where the second node contributes 85%, which is probably you meant by 4.85.

\documentclass{article}
%%%<
\usepackage{verbatim}
\usepackage[active,tightpage,floats]{preview}
\setlength\PreviewBorder{5pt}%
%%%>

\usepackage{tikz}
\usetikzlibrary{shapes}
\usetikzlibrary{calc}%<-added

\begin{document}

\newcommand{\D}{7} % number of dimensions (config option)
\newcommand{\U}{7} % number of scale units (config option)

\newdimen\R % maximal diagram radius (config option)
\R=3.5cm 
\newdimen\L % radius to put dimension labels (config option)
\L=4cm

\newcommand{\A}{360/\D} % calculated angle between dimension axes  

\begin{figure}[htbp]
 \centering

\begin{tikzpicture}[scale=1]
  \path (0:0cm) coordinate (O); % define coordinate for origin

  % draw the spiderweb
  \foreach \X in {1,...,\D}{
    \draw (\X*\A:0) -- (\X*\A:\R);
  }

  \foreach \Y in {0,...,\U}{
    \foreach \X in {1,...,\D}{
      \path (\X*\A:\Y*\R/\U) coordinate (D\X-\Y);
      \fill (D\X-\Y) circle (1pt);
    }
    \draw [opacity=0.3] (0:\Y*\R/\U) \foreach \X in {1,...,\D}{
        -- (\X*\A:\Y*\R/\U)
    } -- cycle;
  }

  % define labels for each dimension axis (names config option)
  \path (1*\A:\L) node (L1) {\tiny Security};
  \path (2*\A:\L) node (L2) {\tiny Content Quality};
  \path (3*\A:\L) node (L3) {\tiny Performance};
  \path (4*\A:\L) node (L4) {\tiny Stability};
  \path (5*\A:\L) node (L5) {\tiny Usability};
  \path (6*\A:\L) node (L6) {\tiny Generality};
  \path (7*\A:\L) node (L7) {\tiny Popularity};

  % Example Case (blue)
  \draw [color=blue,line width=1.5pt,opacity=0.5]
    ($(D1-1)!0.5!(D1-2)$) --
    (D2-6.5) --
    (D3-4.2) --
    ($(D4-4)!0.85!(D4-5)$) --
    (D5-3.6) --
    (D6-5.1) --
    (D7-2.3) -- cycle;

\end{tikzpicture}
\caption{Spiderweb Diagram (\D~Dimensions, \U-Notch Scale, 3 Samples)}
\label{fig:spiderweb}
\end{figure}

\end{document}