xyz2asc

            Function to write a .asc or .txt file with a regular grid form X Y Z matrixes

Inputs
filename   file name
X Y        coordinate matrixes
noval      remplace nan value in Z matrix
n          data precision


Example
[X,Y]=meshgrid(0:.01:1);
Z=sin(X)+cos(Y);
xyz2asc('example.asc',X,Y,Z,-9999,2);