Looks like you're right, seems it gave you googles terrain option. Strange I don't recall seeing that option, must be age catching up with me!
Is your Aperture library still compatible with iPhoto? If so you could switch to iPhoto to do the location tagging. Failing that, you could temporarily move your photos; say create an iPhoto library out of the images in an Aperture project. Tag them in iPhoto and then move them back to Aperture by importing the iPhoto library. Bit of a faff but might get you there.
Also send a feedback request to ask for the terrain feature back.
Another option could be to explore tagging in a different app that creates XMP sidecar file with the location info, pat the sidecar with the master and then seeing if Aperture will import the data with 'update from original'.
Andy