how to color a surface?

Evrytime i try to color a surface the entire plot comes out to be pitch black in color. i tried these codes..please temme if they r right or wrong.

figure(6)
colormap hsv
surf(ti,X,P_s)
colorbar
ylabel('Distance along pipeline (m)')
xlabel('time (hours)')
zlabel('Pressure (bar)')
grid on

plzz help!

[Image Analyst]

I see you using the colormap function - doesn't that color it?

[roro6992]

NO thts d problem...i cant undastnd y its not coloring the plot. the whole plot turns out to be pitch black evry time i execute the code.

[Walter Roberson]

What are max() and min() of P_s(:) ?

Does the problem still occur if you do not have "grid on" ?

[roro6992]

P_s max is 50 and minn is 38..its a plot of pressure vs time and distance. Matrices are of correct dimensions. the surf command is getting executed. but m not getting any colored plot. its a black surface on which no variations of preesure cud be understood. Its still occurin evn wen the grid is off.

[Walter Roberson]

To check: do you get a colored plot if you do not use "colormap hsv" ?

[roro6992]

NO...m no way getting a colored plot..evn wen m using colormap hot or colormap gray..or copper

[roro6992]

But the colorbar is showing all the colors n corresponding values!

[Walter Roberson]

Odd... I don't know. A couple of more experiments:

1)

opengl software

This would be to workaround some drawing bugs

2)

surf(ti,X,double(P_s))

This is complete speculation on my part as to what the cause might be.

[roro6992]

When n where to use the opengl software command.?? Anyway thnx for helping man.

[Walter Roberson]

The "opengl" command could be used at any point.

Answer 1

[Youssef Khmou]

I think your data have many isosamples, that makes the colormap concentrated because of the interpolation,add this command before using colormap :

 shading interp