% th, x,y,data
4,-50,-50,  1.63602089
"4,  0,-50,	   NaN"
4, 50,-50,  1.25091252 
4,-50,  0,  0.50077319
4, 50,  0,  0.45250616 
4,-50, 50, -1.27213645
4,  0, 50,         NaN
4, 50, 50, -0.89128855