From db69f1aa18a519b3f8a00adf1472677c31172d3e Mon Sep 17 00:00:00 2001
From: Max Jones <14077947+maxrjones@users.noreply.github.com>
Date: Mon, 18 Mar 2024 19:52:33 -0400
Subject: [PATCH] Add type alias for projection options

Co-authored-by: Raphael Hagen <norlandrhagen@gmail.com>
---
 ndpyramid/common.py    | 5 ++++-
 ndpyramid/reproject.py | 7 +++----
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/ndpyramid/common.py b/ndpyramid/common.py
index 1fdbf3f..b4c42c4 100644
--- a/ndpyramid/common.py
+++ b/ndpyramid/common.py
@@ -1,12 +1,15 @@
 import typing
+from typing import TypeAlias
 
 import pydantic
 import pyproj
 import rasterio.transform
 
+ProjectionOptions: TypeAlias = typing.Literal['web-mercator', 'equidistant-cylindrical']
+
 
 class Projection(pydantic.BaseModel):
-    name: typing.Literal['web-mercator', 'equidistant-cylindrical'] = 'web-mercator'
+    name: ProjectionOptions = 'web-mercator'
     _crs: str = pydantic.PrivateAttr()
     _proj = pydantic.PrivateAttr()
 
diff --git a/ndpyramid/reproject.py b/ndpyramid/reproject.py
index 635ba7b..c7a95ce 100644
--- a/ndpyramid/reproject.py
+++ b/ndpyramid/reproject.py
@@ -1,6 +1,5 @@
 from __future__ import annotations  # noqa: F401
 
-import typing
 from collections import defaultdict
 
 import datatree as dt
@@ -8,7 +7,7 @@
 import xarray as xr
 from rasterio.warp import Resampling
 
-from .common import Projection
+from .common import Projection, ProjectionOptions
 from .utils import (
     add_metadata_and_zarr_encoding,
     get_levels,
@@ -31,7 +30,7 @@ def _da_reproject(da, *, dim, crs, resampling, transform):
 def level_reproject(
     ds: xr.Dataset,
     *,
-    projection: typing.Literal['web-mercator', 'equidistant-cylindrical'] = 'web-mercator',
+    projection: ProjectionOptions = 'web-mercator',
     level: int,
     pixels_per_tile: int = 128,
     resampling: str | dict = 'average',
@@ -121,7 +120,7 @@ def level_reproject(
 def pyramid_reproject(
     ds: xr.Dataset,
     *,
-    projection: typing.Literal['web-mercator', 'equidistant-cylindrical'] = 'web-mercator',
+    projection: ProjectionOptions = 'web-mercator',
     levels: int = None,
     pixels_per_tile: int = 128,
     other_chunks: dict = None,