[GRASS-user] Divide raster map using vector line

[Rich Shepard]

   Running 7.3.svn here on Slackware-14.1/-14.2 and looking at both vector
and raster modules I don't see how to overlay a vector map on a raster map
to divide the raster into two sections.

   The raster map has the same value in every cell. I want to change the
value in cells north of a vector map of a road. If there's a workflow
description in the docs please point me to it. Otherwise, please suggest a
procedure to accomplish this.

TIA,

Rich