% th, x,y,data
1,-50,-50,         NaN
1,  0,-50,  1.19721355
1, 50,-50,  0.33323071 
1,-50,  0,  1.42543810
1, 50,  0, -0.71833727 
1,-50, 50, -0.02828314
1,  0, 50, -1.33009589
"1, 50, 50,	   NaN"