[GRASS5] [bug #859] (grass) raster data at lower resolution: no resampling...

[Eric G. Miller]

As far as I can tell, in a nutshell:

The code attempts to map the cell row/col value that is most closely
aligned with the center of the region row/col.  It builds an explicit
column mapping, and leaves the decision to which rows to use for
each row fetch operation.  

It's difficult to follow a lot of that code since it uses globals 
and additionally uses #define's to rename various parts of a global
data structure.  Relevant files include: G.h, opencell.c, get_row.c,
window_map.c, and probably a few others (depending on what you think
is relevant).

All of the low-level byte encoding/compression at the file level is
not relevant to the mapping of cell values to match the region.

-- 
Eric G. Miller <egm2 at jps.net>