How to create two additional columns in a results set to act as axis for a heatmap
Answer originally left by the question author in a comment

Final solution was:

SELECT 
    ..., 
    (((ROW_NUMBER() OVER (ORDER BY (SELECT 1))) -1 ) / @cnt) + 1 AS X,
    (((ROW_NUMBER() OVER (ORDER BY (SELECT 1))) -1 ) % @cnt) + 1 AS X