How to plot a 3D graph?

I wrote a code to measure the temperature in terms of time and depth but when I plot my 3D graph, the temperature's values increased significantly from their 2D values and I would like to know why?

Here is my code:

alpha=0.128e-6;

Ts=-20; Ti=10;

t=linspace(0,2.592*10^6,75); 

z=linspace(0,3,75); 

T=(erf(z./(2*sqrt(alpha.*t)))*(Ti-Ts))+Ts;

[tt,zz]=meshgrid(t,z);

TT=tt.^2-zz.^2;

surf(zz,tt,TT);

xlabel('depth')

ylabel('time')

zlabel('temperature')

Answer 1

[Chad Greene]

This isn't a problem with plotting, it's a problem with your data. See:

hist(TT(:))

Your TT matrix has some pretty big values in it, whereas your T matrix has values mostly in the range of -10 to 10 degrees.

Why aren't you calculating TT the same way you calculated T?

TT=(erf(zz./(2*sqrt(alpha.*tt)))*(Ti-Ts))+Ts;

[Thomas Chateauvert]

I changed my code and my TT but I get a pretty funky graph why?

alpha=0.128e-6;

Ts=-20; Ti=10;

t=linspace(0,2.592*10^6,75); 

z=linspace(0,3,75); 

[tt,zz]=meshgrid(t,z);

TT=(erf(zz./(2*sqrt(alpha.*tt)))*(Ti-Ts))+Ts;

surf(zz,tt,TT);

xlabel('depth')
ylabel('time')
zlabel('temperature')

[Chad Greene]

Without any context it's hard to know what you mean by funky or what the surface should look like. Matlab's plotting the data you're giving it, so I can only assume the issue is with the data. Be descriptive about what's wrong with the surface above, and what you want it to look like.

[Chad Greene]

Did you mix up the order of zz and tt when plotting? Try this:

pcolor(tt,zz,TT);
shading interp

xlabel('time')
ylabel('depth')

set(gca,'YDir','reverse') 
cb = colorbar; 
ylabel(cb,'temperature')

Note I opted for pcolor although surfaces look cool, they're rarely of great use for displaying scientific data.