Use m.in.stf1.tape (or ....db3 from CD-ROM) per instructions in the
GRASS Tiger Tutorial on the moon server to extract tract/block maps.
How to use awk is given there. Note that the stf (demographic
population/housing data) for blocks is likely to be inaccurate--statistically
correct, but inaccurate for specific blocks-- so if you label a
block map with population from the stf1b or pl94 files, you can't
rely on specific numbers.
Jim Hinthorne
CWU GIS Lab