# ListVectorPlot on a section of a circle

Can anyone help, why ListVectorPlot and ListStreamPlot show vectors and streamlines lying outside the allowed domain? Here is my Mathematica code:

pp = Table[{r Cos[ϕ], r Sin[ϕ]}, {r, 0, 10,
0.5}, {ϕ, -π/6, π/6, 0.1}];
vv = Table[{{r Cos[ϕ], r Sin[ϕ]}, {1, 0}}, {r, 0, 10,
0.5}, {ϕ, -π/6, π/6, 0.1}];
GraphicsRow[{ListPlot[pp], ListVectorPlot[vv], ListStreamPlot[vv]}]


And I get the plots:

Why do the vectors in the second and third cases fill the whole square instead of the section of a circle?

• Because ListVectorPlot performs interpolation. – Feyre Oct 28 '16 at 21:50

region = Function[{x, y, vx, vy, n},