[i,j] = matrixcoordf(F, X, Y) returns the coordinates of the closest 
matrix element corresponding to the point (X,Y) expressed in physical 
units, using the spatial calibration of the field F. 
 
Attention: Different matrix indexing conventions are used in Matlab and 
PIVMat! According to the PIVMat convention, the first index I is 
horizontal, and the second index J is vertical. 
 

showf, probef. 
Published output in the Help browser 
   showdemo matrixcoordf