180 degree offset of r.slope.aspect (& now s.surf.tps)

Hello fellow GRASSuser's,
Maybe I'm just thick, or still have too much holiday food clogging my arteries,
but I can't understand why r.slope.aspect gives a ZERO value for due east,
and then counts off counter-clockwise. Why not start with due north and go
clockwise, just like a trusty Ranger compass? Can anyone explain the reasoning
(or necessity) behind this?
  Also, any hints from anyone on how to adjust an aspect map to a TRUE
AZIMUTH map, besides manual renumbering?
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   Ronald Thomas ^ ront@meeker.cfnr.colostate.edu
    Natural Resource Spec. (GIS) ^
     Resource Management Division ^ Phone: 303-586-3565 x285
      Rocky Mountain National Park ^ 700-323-7285 (FTS)
       Estes Park, CO 80517 ^
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