Do you need the row and column labels to be part of the grid? Rather than using Row, Column, Overlay, GraphicsGrid, …, consider using MatrixPlot with Epilog and custom Ticks. Take a look at this for an example.
Do you need the row and column labels to be part of the grid? Rather than using Row, Column, Overlay, GraphicsGrid, …, consider using MatrixPlot with Epilog and custom Ticks. Take a look at this for an example.