help with spheroid

[Virginia Jackson]

Hello Grass Users,

Thank you for all your help in the past.  I now have another 
opportunity for you to help me understand GRASS (and probably the 
GIS world) a little better.

My understanding is that a spheroid must be associated with a 
location when the location is created in GRASS.  What are the 
advantages and disadvantages of selecting a spheroid at this time?  

For example, am I limited to working within that spheroid for all
data in that location set?  

If a database was initialized with one spheroid, clark66, can
it be switched to another spheroid, wgs84, without re-inputting the
vector and raster data?

Please bear with me as I gradually learn about the GIS world.
Feel free to respond to me directly.

Virginia Jackson
Engineering Research Associates
e-mail:  jackson at era.com