2D colors above 3D surface plot

Question

I would like to draw a 2D, colored plot of a function above its surface plot.

I tried copying the surface plot and setting z filter/.code={\def\pgfmathresult{1.4}}, but then everything is the same color on the 2D plot.

Also, I'd be glad if I could avoid the antialiasing artifacts on the 2D plot (each quad is made of two triangles, and there is a small white line between them).

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{calc}
\usepackage{pgfplots}
\pgfplotsset{compat=1.7}
\begin{document}
\begin{tikzpicture}
  \begin{axis}[grid=both]
    \addplot3[
    surf,
    shader=faceted interp,
    samples=10,
    ] {sin(deg(x))*sin(deg(y))};

    \addplot3[
    surf,
    shader=faceted interp,
    samples=10,
    z filter/.code={\def\pgfmathresult{1.4}}
    ] {sin(deg(x))*sin(deg(y))};
  \end{axis}
\end{tikzpicture}
\end{document}

Answer 1

The color of the plot depends on the meta value, which by default, is the z value in 3D plots. You can set it to something else, however: In this case, you'd say point meta={sin(deg(x))*sin(deg(y))} (so you'd use the original function for the meta value), and simply plot {1.4} instead of the function:

About the artifacts: That's probably a viewer issue. I don't see them using Adobe Reader or Evince on Ubuntu Linux.

\documentclass[border=5mm]{standalone}
\usepackage{tikz}
\usetikzlibrary{calc}
\usepackage{pgfplots}
\pgfplotsset{compat=1.7}
\begin{document}
\begin{tikzpicture}
  \begin{axis}[grid=both]
    \addplot3[
    surf,
    shader=faceted interp,
    samples=10,
    ] {sin(deg(x))*sin(deg(y))};

    \addplot3[
    surf,
    shader=faceted interp,
    samples=10,point meta rel=per plot,
    point meta={sin(deg(x))*sin(deg(y))}
    ] {1.4};
  \end{axis}
\end{tikzpicture}
\end{document}