How to Draw contour in octave

Contours are used in map creation. Let our function be: x2 + y2. Let us generate a contour map that shows the contour lines for a given function z = f(x, y). This function has two variables x and y.

octave:1> x=-6:6;

octave:1> x=-7:7;

octave:3> [x,y] = meshgrid(-6:0.1:6,-7:0.1:7); //create datasets for 2 variables. 0.1 is a incremental factor.

octave:4> z = x.^2 + y.^2;   //function according to which we will generate contour.

octave:9> [c,h]=contour(z)  //create contour. c is a no. of contour levels.

octave:9> [c,h]=contourf(z) // fill color in contour.

octave:10> set(h,’ShowText’,’on’,’TextStep’,get(h,’LevelStep’)*2) // show value at each contour line.

Screenshot from 2015-06-22 21:06:43

for more options type  octave:1> help contour on terminal. OR follow below links.

http://www.tutorialspoint.com/matlab/matlab_graphics.html

http://in.mathworks.com/help/matlab/ref/colormap.html#budgl13

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