关闭 PGFPLOTS 中的颜色插值

Question

我想绘制一个热图样式的图表，其中只有 2d 矩阵的对角线有值。我期望图表只包含表示对角线元素上的值 > 0 的颜色。然而，我得到的却是这样的：

以下是 MWE：

\documentclass{article}

\usepackage{pgfplots, filecontents}
\pgfplotsset{compat=newest}

\begin{filecontents}{heatmap.dat}
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9.000000000000000000e+00 0.000000000000000000e+00 0.000000000000000000e+00

0.000000000000000000e+00 1.000000000000000000e+00 0.000000000000000000e+00
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0.000000000000000000e+00 7.000000000000000000e+00 0.000000000000000000e+00
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4.000000000000000000e+00 7.000000000000000000e+00 0.000000000000000000e+00
5.000000000000000000e+00 7.000000000000000000e+00 0.000000000000000000e+00
6.000000000000000000e+00 7.000000000000000000e+00 0.000000000000000000e+00
7.000000000000000000e+00 7.000000000000000000e+00 9.573177461885088446e-01
8.000000000000000000e+00 7.000000000000000000e+00 0.000000000000000000e+00
9.000000000000000000e+00 7.000000000000000000e+00 0.000000000000000000e+00

0.000000000000000000e+00 8.000000000000000000e+00 0.000000000000000000e+00
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0.000000000000000000e+00 9.000000000000000000e+00 0.000000000000000000e+00
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6.000000000000000000e+00 9.000000000000000000e+00 0.000000000000000000e+00
7.000000000000000000e+00 9.000000000000000000e+00 0.000000000000000000e+00
8.000000000000000000e+00 9.000000000000000000e+00 0.000000000000000000e+00
9.000000000000000000e+00 9.000000000000000000e+00 9.189678833446063289e-01
\end{filecontents}

\begin{document}

\begin{figure}
  \centering
  \begin{tikzpicture}
    \begin{axis}[view={0}{90},
        colorbar,
        y dir=reverse,
        xlabel=$x$,
        ylabel=$y$,]
      \addplot3[surf, shader=faceted] table {heatmap.dat};
    \end{axis}
  \end{tikzpicture}
  \caption{Heatmap with PGFPLOTS}
\end{figure}

\end{document}

在这种情况下我该如何关闭颜色插值？

Answer 1

您很可能正在寻找shader=flat corner。

\documentclass{article}

\usepackage{pgfplots}
\pgfplotsset{compat=newest}

\begin{filecontents}[overwrite]{heatmap.dat}
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9.000000000000000000e+00 9.000000000000000000e+00 9.189678833446063289e-01
\end{filecontents}

\begin{document}

\begin{figure}
  \centering
  \begin{tikzpicture}
    \begin{axis}[view={0}{90},
        colorbar,
        y dir=reverse,
        xlabel=$x$,
        ylabel=$y$,]
      \addplot3[surf, shader=flat corner] table {heatmap.dat};
    \end{axis}
  \end{tikzpicture}
  \caption{Heatmap with PGFPLOTS}
\end{figure}

\end{document}