grayplot

Arguments

x, y, z

Real matrices defining the grid and the surface values : x and y can be row vectors of sizes n1 and n2 and z a real matrix of size (n1,n2) (rectangular grid) or the 3 matrices can have the same size (n1,n2) (curvilinear grid).

<opt_args>

This represents a sequence of statements key1=value1, key2=value2 ,... where key1, key2,... can be one of the following: rect, nax, strf, logflag or axesflag and frameflag (see plot2d).

strf,rect,nax

see plot2d.

h

This optional output contains a handle to a Grayplot entity. Use h to modify its properties. For a list of properties, see grayplot_properties.

Description

grayplot makes a 2D pseudo-color plot of the surface z on the grid defined by x and y. Each cell of the grid is filled with a gray or color level depending on the average value of z at its corners. If z contains %nan values, the surrounding cells are not displayed. When x and y are vectors the grid is rectangular; when x, y and z are all matrices of the same size the grid is non-rectangular, with node (i,j) located at (x(i,j), y(i,j)) — useful for curvilinear or polar coordinates.

Enter the command grayplot() to see a demo.

Examples

x=-10:10;
y=-10:10;
m=rand(21,21);
grayplot(x,y,m,rect=[-20,-20,20,20])

t=-%pi:0.1:%pi;
m=sin(t)'*cos(t);
clf()
grayplot(t,t,m)

// Non-rectangular grid: sector of an annulus in polar coordinates
[R,T] = ndgrid(linspace(0.1,1,100), linspace(0,%pi/4,50));
grayplot(R.*cos(T), R.*sin(T), rand(T))

See also

• fgrayplot — 2D plot of a surface defined by a function using colors
• plot2d — 2D plot
• Sgrayplot — smooth 2D plot of a surface using colors
• Sfgrayplot — smooth 2D plot of a surface defined by a function using colors

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