3 D data rapresentation

I have a matrix of values (large part are zero), and two vectors of coordinates, x and y, that defines the matrix in which I have the values of the point. I use mesh(x,y,imageMag) to plot the data, but I wuold like to see the peaks sharper. Is it possible? After that I would like to compute the volume under the surface I have plotted with mesh (physically it rappresents a power and I have to check if is it constant)

[KSSV]

Is the data of a grid? Attach data here. It would be easy to understand.