Halliday & Matthiessen (2014: 318):
Abstract space is the source of various expressions that serve as realisations of other types of circumstance such as Manner (e.g. walk on one’s legs, make wine out of grapes), Rôle (e.g. cut into cubes, translate from Spanish into English). It can be difficult to determine whether such an expression serves as an abstract Location or as a circumstance of another type. But probes involving Wh– items usually help us draw the line. For example, using the spatial where, we can say where the dollar rose was to its highest point in the past year, which indicates that to its highest point in the past year is a Location in abstract space rather than a circumstance of some other kind. In contrast, we cannot say where she talked was on the meaning of life, which indicates that on the meaning of life is not a Location in abstract space but rather a circumstance of another kind.