Getting sort clauses was added officially in master a few weeks back, however when testing this together with Query Type it is clear it is a bit more difficult then it have to be. As it would imply you'll have to make the query type a service and rely on search service, which feels a bit backwards.

So this can be simplified if the mapping was on Location object itself, reducing the need for having access to both the full Location and Search Service which is the case now, to just need to have the (parent) Location.