When you drag images onto the Map in Lightroom’s Map module, and you have Reverse Geocoding enabled (Catalog Settings > Metadata > Reverse Geoencoding), Lightroom will automatically enter Location information associated with the GPS information (Sublocation, City, State/Province, Country, and ISO Country Code).
It’s important to note that Lightroom can treat the Location Information and the GPS data independently of one another. If you move the location of the images (by dragging and dropping them to another location on the map), by default both the GPS as well as the Location Information will be updated. In fact, this is always true of the GPS information – if you move the image on the map, the GPS data will be updated.
You have, however, the option to override the Location Information. As I mentioned, by default, Lightroom will update the Location Information if you move the file, but you can also change the Location Information manually (perhaps you have a nickname for the location), by typing in any of the Location Information fields.
Lightroom displays the Location Information in grey if it is being automatically generated. If you customize the values (enter your own text), the custom information displays in white. Note: In both scenarios, the location Information will be exported with the file.
As you can see in the first example, the Location Information is gray indicating that Lightroom assigned the information based on reverse geoencoding the GPS data.
In the second example, I have entered “Ferry Plaza Farmers Market” in the Sublocation – overriding Lightroom’s reverse geoencoding information – locking it in so that moving the image on the Map will no longer automatically update it.