How to use contour functions with data

Hello everyone. I've measured the directivity of a loudspeaker and I'm looking for ways to display my data in a more attrative way than a simple polar graph. I have a set of data that correspononds to dbFS (digital level) vs. frequency (with let's say 7000 values), for different angles (from 0º up to 345º with 15º intervals=24), so no math functions here, just empiric numbers. I'd like to plot the data into something like http://www.princeton.edu/3D3A/Directivity/Quad_ESL57/6.QuadESL57ContHor.jpg which would be a contourf function I guess. I've searched for this but haven't been lucky finding anything that I can understand. Any help will be appreciated. Thank you