Map Reprojection

Q: How to change map/image projections, datums, etc in GRASS GIS?

1. create an import location in the projection and datum of the map/image you want to import
2. import the map/image into the location
3. create a destination location in the projection and datum you want to reproject the map/image into
4. working in the destination location, use r.proj or v.proj (depending on whether the map/image is raster or vector) to reproject the map/image from the import location to the destination location.