There are functions available in MATLAB which can perform 1-D, 2-D, or 3-D data interpolation. The function names are 'interp1', 'interp2' and 'interp3'. Depending on how many variables you have, you can try using the corresponding function to interpolate your data before using 'pcolor' to create the pseudocolor plot.
It may be a good idea to check out the section titled 'Interpolation' in the doc page below:
If you are looking at smoothing the graph, the following answer's post might help: https://www.mathworks.com/matlabcentral/answers/86013-pcolor-how-to-smooth
"shading interp" command might be helpful here as well: https://www.mathworks.com/help/matlab/ref/shading.html
This third-party file-exchange function might also be helpful: https://www.mathworks.com/matlabcentral/fileexchange/35601-sanepcolor-varargin-
There is a MATLAB Example that can help with offset data: https://www.mathworks.com/examples/matlab/community/20093-offsets-and-discarded-data-via-pcolor-and-surf