feat: Add .res property to Overview (#90)

Author: kylebarron

src/async_geotiff/_geotiff.py

@@ -1,6 +1,5 @@
 from __future__ import annotations
 
-import math
 from dataclasses import dataclass, field
 from functools import cached_property
 from typing import TYPE_CHECKING, Self
@@ -351,16 +350,6 @@ def photometric(self) -> PhotometricInterpretation | None:  # noqa: PLR0911
 
         return None
 
-    @property
-    def res(self) -> tuple[float, float]:
-        """Return the (width, height) of pixels in the units of its CRS."""
-        transform = self.transform
-        # For rotated images, resolution is the magnitude of the pixel size
-        # calculated from the transform matrix components
-        res_x = math.sqrt(transform.a**2 + transform.d**2)
-        res_y = math.sqrt(transform.b**2 + transform.e**2)
-        return (res_x, res_y)
-
     @property
     def shape(self) -> tuple[int, int]:
         """Get the shape (height, width) of the full image."""

src/async_geotiff/_transform.py

@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+import math
 from math import floor
 from typing import TYPE_CHECKING, Literal, Protocol
 
@@ -48,6 +49,18 @@ def index(
 
         return (op(row_frac), op(col_frac))
 
+    @property
+    def res(self: HasTransform) -> tuple[float, float]:
+        """Return the (width, height) of pixels in the units of its CRS."""
+        transform = self.transform
+
+        # For rotated images, resolution is the magnitude of the pixel size
+        # calculated from the transform matrix components
+        res_x = math.sqrt(transform.a**2 + transform.d**2)
+        res_y = math.sqrt(transform.b**2 + transform.e**2)
+
+        return (res_x, res_y)
+
     def xy(
         self: HasTransform,
         row: int,