Alternatively the output matrix may be based on a different pattern of zones by compressing/expanding/re-coding the zones and the corresponding cells in the internal matrix (options 3 to 10).
Note that the options described below closely parallel those described in Section 10.4 for the transformation of the internal matrix. Thus, alternatively, the matrix may be first transformed internally and then output “as is”. For complex transformations, e.g., not a straightforward compression, it may be preferable to undertake the transformation before output as it may be easier to check what is happening.
Zonal re-coding options were originally handled by the SATURN programs M3, M4 and M5. M3 and M4 were basically simplified versions of M5 which would not work with, e.g., stacked matrices so that they have now been effectively phased out (and have been given option numbers at the bottom of the list to reflect this fact). In all three cases the specifications for the new zone structure must be pre-coded on an input data file whose formats follow the previous M3/M4/M5 conventions given in Appendix W.
Option 3 (M5) represents the most general form of zonal transformations in that it allows for zones to be added together (“compressed”), renamed, sub-divided into new zones or deleted as defined in the control file as documented in App W.3. To a large extent M5 duplicates the interactive options described in Section 10.4.2 for editing zones internally.