8x8 test map from stackoverflow
file name test_map.ascii
import with r.in.ascii

GRASS sample data in location nc_spm_08
Landsat
lsat7_2002_*
create a group with outbands 61, 62, 80

grayscale orthophoto
ortho_2001_t792_1m

RGB orthophoto
http://www.grassbook.org/wp-content/uploads/ncexternal/ortho2010_t792_subset_20cm.tif