The picture in the article shows what looks like keypoint matching (ie, SIFT, SURF, FAST) between the query picture and the database. This can give an exact location if a picture of the location exists in their database.
They contrasted this with their prior technique which is more of an image classifier that can identify general location from image features. This approach does not require their database to contain a picture of the exact location.
They contrasted this with their prior technique which is more of an image classifier that can identify general location from image features. This approach does not require their database to contain a picture of the exact location.