diff --git a/read_in.py b/read_in.py
index 7a91d82..b14298f 100644
--- a/read_in.py
+++ b/read_in.py
@@ -124,41 +124,21 @@ def read_elevations(lines: Iterable[str]) -> Result[Iterator[int], UnparsableEle
 		])
 	)
 
-def gb_to_terrain_type(green_blue: Tuple[int, int]) -> Option[Terrain]:
-	"""
-	Maps the green and blue components of a color to a terrain type.
-
-	If no terrain type exists with that color, then `None` is returned.
-
-	>>> gb_to_terrain_type((192, 0))
-	Some(<Terrain.ROUGH_MEADOW: 700>)
-
-	>>> gb_to_terrain_type((192, 1)) is None
-	True
-	"""
-	match green_blue:
-		case (148, 18):
-			return Some(Terrain.OPEN_LAND)
-		case (192, 0):
-			return Some(Terrain.ROUGH_MEADOW)
-		case (255, 255):
-			return Some(Terrain.EASY_FOREST)
-		case (208, 60):
-			return Some(Terrain.MEDIUM_FOREST)
-		case (136, 40):
-			return Some(Terrain.WALK_FOREST)
-		case (73, 24):
-			return Some(Terrain.BRUSH)
-		case (0, 255):
-			return Some(Terrain.WET)
-		case (51, 3):
-			return Some(Terrain.ROAD)
-		case (0, 0):
-			return Some(Terrain.FOOTPATH)
-		case (0, 101):
-			return Some(Terrain.OOB)
-		case _:
-			return None
+gb_to_terrain_type = {
+	(148, 18): Terrain.OPEN_LAND,
+	(192, 0): Terrain.ROUGH_MEADOW,
+	(255, 255): Terrain.EASY_FOREST,
+	(208, 60): Terrain.MEDIUM_FOREST,
+	(136, 40): Terrain.WALK_FOREST,
+	(73, 24): Terrain.BRUSH,
+	(0, 255): Terrain.WET,
+	(51, 3): Terrain.ROAD,
+	(0, 0): Terrain.FOOTPATH,
+	(0, 101): Terrain.OOB
+}
+"""
+Maps the green and blue components of a color to a terrain type.
+"""
 
 class UnrecognizedColor(NamedTuple):
     "A color in a provided map was not in the list of recognized colors"
@@ -186,10 +166,7 @@ def load_gb_pixels_as_map(pixels: Iterable[Tuple[int, int]]) -> Result[Sequence[
     coordinates of the pixel which could not be identified.
     """
     return sequence([
-        note(
-			lambda: UnrecognizedColor(pix_no % 395, pix_no // 395),
-            gb_to_terrain_type(gb)
-        )
+        try_(lambda _: UnrecognizedColor(pix_no % 395, pix_no // 395), gb_to_terrain_type.get, gb)
         for (pix_no, gb) in enumerate(pixels)
     ])