Start converting some enum-like strings to proper enums

providers/spot/tiles.py

@@ -4,6 +4,7 @@ from datetime import datetime
 import requests
 
 from core.constants import HTTP_HEADERS
+from core.enums import LocationSourceForSpot
 from data.sig_ref import SIGRef
 from data.spot import Spot
 from providers.spot.http_spot_provider import HTTPSpotProvider
@@ -73,7 +74,7 @@ class Tiles(HTTPSpotProvider):
                 dx_grid=source_spot["maidenhead_grid"],
                 dx_latitude=source_spot["latitude"],
                 dx_longitude=source_spot["longitude"],
-                dx_location_source="GRID",
+                dx_location_source=LocationSourceForSpot.GRID,
             )
 
             # Add to our list. Don't worry about de-duping, removing old spots etc. at this point; other code will do