Graphing in Latex 2

Drawing 3D graph with LATEX

Latex is not limited at two dimension functions, it can also draw three dimentional representation of functions with three variable. For this type of graph we still need the same packages as 2D graph, so add:

CODE


          \usepackage{tikz}

          \usepackage{pgfplot}

before starting the document.

Basic 3D graph.

Exactly like 2D graph, we need first to create the environment for plotting graphs, for that we write:

CODE


         \begin{tikzpicture}

         \begin{axis}[option of the axis]

         ...

         \end{axis}

         \end{tikzpicture}

Now we can insert our function in the environment. There is a small difference between the 2D plot and 3D: for the 3 dimension the code is: \addplot3[surf,]{function}; Here is an example:

CODE


      \begin{tikzpicture}

      \begin{axis}

      \addplot3[surf,]{x^2+y^2};

      \end{axis}

      \end{tikzpicture}

There is also the possibility to draw the function as a grid instead of a surface, change [surf,] to [mesh,]:

CODE


    \begin{tikzpicture}

    \begin{axis}

    \addplot3[mash,]{x+10*y};

    \end{axis}

    \end{tikzpicture}

We can change even the color, add in the option [colormap/cool]:

CODE


   \begin{tikzpicture}

   \begin{axis}

   \addplot3[surf, colormap/cool]{x*y};

   \end{axis}

   \end{tikzpicture}

After the option colormap/ we can use other predefine extension, here are other possible parts: hot, hot2, jet, blackwhite, bluered, greenyellow, redyellow, violet.

Surface from coordinates.

Latex can plot 3D graph not just from function, but also from coordinates to create a surface. Here is an example:

CODE


      \begin{tikzpicture}

      \begin{axis}

      \addplot3[surf,]

      coordinates {

      (0,0,0) (0,1,0) (0,0.5,0)

      (1,0,0) (1,1,1) (1,2,2)

      (2,0,0) (2,1,1) (2,2,2)};

      \end{axis}

      \end{tikzpicture}

Exercice.

Now try to display the function: f(x,y)=x+y^3
for the solution move the mouse over the black box on the right


              \begin{tikzpicture}

              \begin{axis}

              \addplot3[surf,]{x+y^3};

              \end{axis}

              \end{tikzpicture}