feat: Implement bounds, res, and shape, and xy (#9)

Author: kylebarron

pyproject.toml

@@ -17,6 +17,7 @@ morecantile = ["morecantile>=7.0,<8.0"]
 
 [dependency-groups]
 dev = [
+    "affine>=3.0rc1",
     "ipykernel>=7.1.0",
     "obstore>=0.8.2",
     "pytest>=9.0.2",

src/async_geotiff/_geotiff.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+from functools import cached_property
 from typing import TYPE_CHECKING, Literal, Self
 
 from affine import Affine
@@ -95,14 +96,18 @@ def block_size(self, bidx: int, i: int, j: int) -> int:
         """
         raise NotImplementedError()
 
-    @property
+    @cached_property
     def bounds(self) -> tuple[float, float, float, float]:
         """Returns the bounds of the dataset in the units of its coordinate reference system.
 
         Returns:
             (lower left x, lower left y, upper right x, upper right y)
         """
-        raise NotImplementedError()
+        transform = self.transform
+        (left, top) = transform * (0, 0)
+        (right, bottom) = transform * (self.width, self.height)
+
+        return (left, bottom, right, top)
 
     @property
     def colorinterp(self) -> list[str]:
@@ -201,9 +206,13 @@ def is_tiled(self) -> bool:
         raise NotImplementedError()
 
     @property
-    def nodata(self) -> float | int | None:
+    def nodata(self) -> float | None:
         """The dataset's single nodata value."""
-        raise NotImplementedError()
+        nodata = self._primary_ifd.gdal_nodata
+        if nodata is None:
+            return None
+
+        return float(nodata)
 
     @property
     def photometric(self) -> PhotometricInterp | None:
@@ -212,17 +221,18 @@ def photometric(self) -> PhotometricInterp | None:
         # https://rasterio.readthedocs.io/en/stable/api/rasterio.enums.html#rasterio.enums.PhotometricInterp
         raise NotImplementedError()
 
-    @property
+    @cached_property
     def res(self) -> tuple[float, float]:
         """Returns the (width, height) of pixels in the units of its coordinate reference system."""
-        raise NotImplementedError()
+        transform = self.transform
+        return (transform.a, -transform.e)
 
     @property
     def shape(self) -> tuple[int, int]:
         """Get the shape (height, width) of the full image."""
-        raise NotImplementedError()
+        return (self.height, self.width)
 
-    @property
+    @cached_property
     def transform(self) -> Affine:
         """The dataset's georeferencing transformation matrix
 
@@ -275,12 +285,12 @@ def xy(
         self,
         row: int,
         col: int,
-        offset: Literal["center", "ul", "ur", "ll", "lr"] = "center",
+        offset: Literal["center", "ul", "ur", "ll", "lr"] | str = "center",
     ) -> tuple[float, float]:
         """Get the coordinates x, y of a pixel at row, col.
 
         The pixel's center is returned by default, but a corner can be returned
-        by setting `offset` to one of `ul, ur, ll, lr`.
+        by setting `offset` to one of `"ul"`, `"ur"`, `"ll"`, `"lr"`.
 
         Parameters:
             row: Pixel row.
@@ -289,7 +299,27 @@ def xy(
                 pixel or for a corner.
 
         """
-        raise NotImplementedError()
+        transform = self.transform
+
+        if offset == "center":
+            c = col + 0.5
+            r = row + 0.5
+        elif offset == "ul":
+            c = col
+            r = row
+        elif offset == "ur":
+            c = col + 1
+            r = row
+        elif offset == "ll":
+            c = col
+            r = row + 1
+        elif offset == "lr":
+            c = col + 1
+            r = row + 1
+        else:
+            raise ValueError(f"Invalid offset value: {offset}")
+
+        return transform * (c, r)
 
 
 def has_geokeys(ifd: ImageFileDirectory) -> bool:

tests/test_geotiff.py

@@ -9,27 +9,51 @@
 if TYPE_CHECKING:
     from rasterio.io import DatasetReader
 
+    LoadGeoTIFF = Callable[[str], Awaitable[GeoTIFF]]
+    LoadRasterio = Callable[[str], DatasetReader]
+
 
 @pytest.mark.asyncio
-async def test_height_width(
-    load_geotiff: Callable[[str], Awaitable[GeoTIFF]],
-    load_rasterio: Callable[[str], DatasetReader],
-) -> None:
+async def test_bounds(load_geotiff: LoadGeoTIFF, load_rasterio: LoadRasterio) -> None:
     name = "uint8_rgb_deflate_block64_cog"
 
     geotiff = await load_geotiff(name)
     with load_rasterio(name) as rasterio_ds:
-        assert rasterio_ds.height == geotiff.height
-        assert rasterio_ds.width == geotiff.width
+        assert rasterio_ds.bounds == geotiff.bounds
 
 
 @pytest.mark.asyncio
 async def test_transform(
-    load_geotiff: Callable[[str], Awaitable[GeoTIFF]],
-    load_rasterio: Callable[[str], DatasetReader],
+    load_geotiff: LoadGeoTIFF, load_rasterio: LoadRasterio
 ) -> None:
     name = "uint8_rgb_deflate_block64_cog"
 
     geotiff = await load_geotiff(name)
     with load_rasterio(name) as rasterio_ds:
         assert rasterio_ds.transform == geotiff.transform
+        assert rasterio_ds.height == geotiff.height
+        assert rasterio_ds.width == geotiff.width
+        assert rasterio_ds.shape == geotiff.shape
+        assert rasterio_ds.res == geotiff.res
+
+
+@pytest.mark.asyncio
+async def test_xy(load_geotiff: LoadGeoTIFF, load_rasterio: LoadRasterio) -> None:
+    name = "uint8_rgb_deflate_block64_cog"
+
+    geotiff = await load_geotiff(name)
+
+    x = geotiff.width // 2
+    y = geotiff.height // 2
+
+    with load_rasterio(name) as rasterio_ds:
+        for offset in ["center", "ul", "ur", "ll", "lr"]:
+            assert rasterio_ds.xy(
+                x,
+                y,
+                offset=offset,
+            ) == geotiff.xy(
+                x,
+                y,
+                offset=offset,
+            )