How to extract matrix from fit function or sfit result or Curve Fitting Tool??

I used Curve Fitting Tool and FIt Fuction.

===========Fit function===================

[xData, yData, zData] = prepareSurfaceData( xxx, yyy, zzz );

ft = 'nearestinterp';

[fitresult, gof] = fit( [xData, yData], zData, ft, 'Normalize', 'on' );

============Curve Fitting Tool=============

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So my question is as below!

1. I want to extract the matrix like the picture above.In other words, I want to extract the matrix for zzz.

2. I would also like to extract whether the xxx and yyy coordinates are located in the extracted matrix.