[GRASS-dev] r.walk/r.cost/r.drain updates

[Colin Nielsen]

Hi developers,
I have updated the r.walk, r.cost and r.drain modules to include
"back-link raster" functionality. Currently the path created by
r.drain does not necessarily take THE path through a cost surface,
that the cost accumulation algorithm took to generate that cost
surface. My updates add an "outdir" raster as an output from the
r.drain and r.cost modules which creates a backlink raster, or a
raster surface of the movements made to create the cost surface
(recorded in degrees). I then modified r.drain to read this surface
when it's given the "-d" flag.

The changes I have made to these modules will be submitted as a patch
to the trac system relatively soon, but I have a few questions first.

1) I started the changes to r.walk and r.drain on code downloaded last
June, labeled as "grass-6.3.0RC6." And added the functionality to
r.cost at the end of october to a version I checked out using "svn
checkout https://svn.osgeo.org/grass/grass/branches/develbranch_6". My
question is, how do I submit these patches in a way that doesn't
over-write subsequent changes (especially the earlier ones)? Should I
re-write the r.walk and r.drain updates into a more recent version?

2) Do I simply attach the .patch files to a new ticket?

Thanks for your help,

-Colin