Matlab -- how to make a smooth contour plot?

[kelvin490]

I want to represent data with 2 variables in 2D format. The value is represented by color and the 2 variables as the 2 axis. I am using the contourf function to plot my data:

load('data.mat')
cMap=jet(256);
F2=figure(1);

[c,h]=contourf(xrow,ycol,BDmatrix);
set(h, 'edgecolor','none');
Both xrow and ycol are 6x6 matrices representing the coordinates. BDmatrix is the 6x6 matrix representing the corresponding data. However, what I got the picture as attached.

Would it be possible for the contour color to vary smoothly rather than appearing as straight lines joining the data points? The problem of this figure is the coarse-granularity which is not appealing. I have tried to replace contourf with imagec but it seems not working. I am using MATLAB R2015b.

 

[marcusl]

You are seeing the effects of plotting on just a 6x6 grid. The contours would look smooth if your data were on, say, a 200x200 grid. I don't know what to do except to generate denser data or maybe look for software that uses different contour generation methods.

 

[FactChecker]

MATLAB has a color shading property that might interpolate between colors using the option "shading interp". I can not test this, but you might try it. (see https://www.mathworks.com/help/matlab/ref/shading.html?s_tid=gn_loc_drop )

 

[Image Analyst]

Try using interp2() or griddedInterpolant() to make more data point locations before passing the image to contourf().