This is the map that Aitrus, of the Guild of Surveyors,
made while the Guilds of Miners dug toward the surface. The D'ni text in the
upper-left corner says "meh-D'nee breh-TAHL-ee-oh",
which means "From D'ni to the Surface". Go to Cyan's old site to see close-ups
and translations of the various D'ni texts on the map:
http://sirrus.cyan.com/Online/D%27ni/DniMap

I will point out, however, that Cyan doesn't show,
or translate, the D'ni text below the Timepiece, in the bottom-left corner. We
know the basics of D'ni time, and I fail to see why
Aitrus would explain them on his map, so the translation of that text is still
a mystery. And Rawa isn't telling (as usual :)) ...