contourf — filled level curves of a surface on a 2D plot
contourf(x,y,z,nz,[style,strf,leg,rect,nax])
two real row vectors of size n1 and n2: the grid.
real matrix of size (n1,n2), the values of the function.
the level values or the number of levels.
If nz is an integer, its value gives
the number of level curves equally spaced from zmin to zmax as
follows:
z= zmin + (1:nz)*(zmax-zmin)/(nz+1)
Note: that the zmin and
zmax levels are not drawn (generically they
are reduced to points) but they can be added with
[im,jm] = find(z == zmin); // or zmax
plot2d(x(im)',y(jm)',-9,"000")
If nz is a vector,
nz(i) gives the value of the ith level
curve.
see plot2d. The argument
style gives the colors which are to be used for
level curves. It must have the same size as the number of
levels.
contourf paints surface between two consecutives
level curves of a surface z=f(x,y) on a 2D plot. The
values of f(x,y) are given by the matrix
z at the grid points defined by x
and y.
You can change the format of the floating point number printed on
the levels by using xset("fpf",string) where
string gives the format in C format syntax (for example
string="%.3f"). Use string="" to
switch back to default format.
Enter the command contourf() to see a
demo.
contourf(1:10,1:10,rand(10,10),5,1:5,"011"," ",[0,0,11,11])
function z=peaks(x,y)
x1=x(:).*.ones(1,size(y,'*'));
y1=y(:)'.*.ones(size(x,'*'),1);
z = (3*(1-x1).^2).*exp(-(x1.^2) - (y1+1).^2) ...
- 10*(x1/5 - x1.^3 - y1.^5).*exp(-x1.^2-y1.^2) ...
- 1/3*exp(-(x1+1).^2 - y1.^2)
endfunction
function z=peakit()
x=-4:0.1:4;y=x;z=peaks(x,y);
endfunction
z=peakit();
levels=[-6:-1,-logspace(-5,0,10),logspace(-5,0,10),1:8];
m=size(levels,'*');
n = fix(3/8*m);
r = [(1:n)'/n; ones(m-n,1)];
g = [zeros(n,1); (1:n)'/n; ones(m-2*n,1)];
b = [zeros(2*n,1); (1:m-2*n)'/(m-2*n)];
h = [r g b];
xset('colormap',h);
xset('fpf',' ');
xbasc();
contourf([],[],z,[-6:-1,-logspace(-5,0,10),logspace(-5,0,10),1:8],0*ones(1,m))
xset('fpf','');
xbasc();
contourf([],[],z,[-6:-1,-logspace(-5,0,10),logspace(-5,0,10),1:8]);