I have some Table of `{x,y,z}` values (energy as a function of radial and azimuthal frequencies in a galaxy if you care to know): dat = Import["https://dl.dropboxusercontent.com/u/659996/odd-data.m"]; If I plot the position of the `{x,y}` pl1 = Most /@ Flatten[dat, 1] // ListPlot I get this ![Mathematica graphics](https://i.sstatic.net/dtS2f.png) Note that there is nothing pathological in the distribution of points as seen from this 3D view Map[{Hue[#[[3]]], Point[#]} &, Flatten[dat, 1]] // Graphics3D ![Mathematica graphics](https://i.sstatic.net/mP2wC.png) If I now plot contours of `z[x,y]`, I get that: pl2 = ListContourPlot[Flatten[dat, 1], PlotLegends -> Automatic,PlotRange -> All] ![Mathematica graphics](https://i.sstatic.net/uCy63.png) **PROBLEM** Now the puzzling fact is that it seems mathematica gives me contours at values of `{x,y}` which I have not sampled. This is best seen in the superposition: Show[pl2, pl1] ![Mathematica graphics](https://i.sstatic.net/DM4bH.png) e.g. for values of `x=0.3 y=0.175`. **QUESTION** > Is this a bug? or am I missing something obvious?