See this:
http://community.boredofstudies.org/showthread.php?t=297952
There's a link in one of the posts: gparank.pdf
There you'll find a table that converts gpa to an academic rank.
NRSL = (academic rank + ATAR) / 2
I believe that some universities use NRSL when considering non standards seeking entry into a particular course.
I know that USYD considers both ATAR and GPA for entry into their Law program.
