✨ Implement xy_coords method on PyCudaCogReader struct

python/cog3pio/__init__.pyi

@@ -76,7 +76,7 @@ class CogReader:
 
         Determined based on an Affine transformation matrix built from the
         `ModelPixelScaleTag` and `ModelTiepointTag` TIFF tags. Note that non-zero
-        rotation (set by `ModelTransformationTag` is currently unsupported.
+        rotation (set by `ModelTransformationTag`) is currently unsupported.
 
         Returns
         -------
@@ -206,6 +206,20 @@ class CudaCogReader:
         device : (int, int)
             A tuple (`device_type`, `device_id`) in DLPack format.
         """
+    def xy_coords(self) -> tuple[numpy.typing.NDArray[numpy.float64], numpy.typing.NDArray[numpy.float64]]:
+        r"""
+        Get list of x and y coordinates.
+
+        Determined based on an Affine transformation matrix built from the
+        `ModelPixelScaleTag` and `ModelTiepointTag` TIFF tags. Note that non-zero
+        rotation (set by `ModelTransformationTag`) is currently unsupported.
+
+        Returns
+        -------
+        coords : (numpy.ndarray, numpy.ndarray)
+            A tuple (x_coords, y_coords) of numpy.ndarray objects representing the
+            GeoTIFF's x- and y-coordinates.
+        """
 
 def read_geotiff(path: builtins.str) -> numpy.typing.NDArray[numpy.float32]:
     r"""

python/tests/test_io_geotiff.py

@@ -116,7 +116,7 @@ def test_read_geotiff_unsupported_dtype():
         )
 
 
-def test_CogReader_to_dlpack():
+def test_cogReader_to_dlpack():
     """
     Ensure that the CogReader class's `__dlpack__` method produces a dl_tensor that
     can be read into a numpy.ndarray.
@@ -136,3 +136,34 @@ def test_CogReader_to_dlpack():
             [[[1.41, 1.23, 0.78], [0.32, -0.23, -1.88]]], dtype=np.float32
         ),
     )
+
+
+def test_cogreader_xy_coords():
+    """
+    Ensure that the CogReader class's `xy_coords` method produces two numpy.ndarray
+    objects representing the GeoTIFF's x- and y- coordinates.
+    """
+    cog = CogReader(
+        path="https://github.com/blacha/cogeotiff/raw/core-v9.4.0/packages/core/data/DEM_BS28_2016_1000_1141.tif"
+    )
+    x_coords, y_coords = cog.xy_coords()
+    np.testing.assert_equal(
+        actual=x_coords,
+        desired=np.linspace(
+            start=1679617.031,
+            stop=1679680.031,
+            num=63,
+            endpoint=False,
+            dtype=np.float64,
+        ),
+    )
+    np.testing.assert_equal(
+        actual=y_coords,
+        desired=np.linspace(
+            start=5362323.781,
+            stop=5362079.781,
+            num=244,
+            endpoint=False,
+            dtype=np.float64,
+        ),
+    )

python/tests/test_io_nvtiff.py

@@ -44,6 +44,38 @@ def test_cudacogreader_to_dlpack():
     )
 
 
+def test_cudacogreader_xy_coords():
+    """
+    Ensure that the CudaCogReader class's `xy_coords` method produces two numpy.ndarray
+    objects representing the GeoTIFF's x- and y- coordinates.
+    """
+    cog = CudaCogReader(
+        path="https://github.com/blacha/cogeotiff/raw/core-v9.4.0/packages/core/data/DEM_BS28_2016_1000_1141.tif",
+        device_id=0,
+    )
+    x_coords, y_coords = cog.xy_coords()
+    np.testing.assert_equal(
+        actual=x_coords,
+        desired=np.linspace(
+            start=1679617.031,
+            stop=1679680.031,
+            num=63,
+            endpoint=False,
+            dtype=np.float64,
+        ),
+    )
+    np.testing.assert_equal(
+        actual=y_coords,
+        desired=np.linspace(
+            start=5362323.781,
+            stop=5362079.781,
+            num=244,
+            endpoint=False,
+            dtype=np.float64,
+        ),
+    )
+
+
 @pytest.mark.benchmark
 @pytest.mark.parametrize(
     "engine",

src/python/adapters.rs

@@ -115,7 +115,7 @@ impl PyCogReader {
     ///
     /// Determined based on an Affine transformation matrix built from the
     /// `ModelPixelScaleTag` and `ModelTiepointTag` TIFF tags. Note that non-zero
-    /// rotation (set by `ModelTransformationTag` is currently unsupported.
+    /// rotation (set by `ModelTransformationTag`) is currently unsupported.
     ///
     /// Returns
     /// -------

src/python/cudacog.rs

@@ -6,13 +6,15 @@ use bytes::Bytes;
 use cudarc::driver::{CudaContext, CudaStream};
 use dlpark::SafeManagedTensorVersioned;
 use dlpark::ffi::{DLPACK_MAJOR_VERSION, DLPACK_MINOR_VERSION, Device};
+use numpy::{PyArray1, ToPyArray};
 use pyo3::exceptions::{PyBufferError, PyNotImplementedError, PyValueError, PyWarning};
-use pyo3::{PyResult, pyclass, pymethods};
+use pyo3::{Bound, PyResult, Python, pyclass, pymethods};
 use pyo3_stub_gen::define_stub_info_gatherer;
 use pyo3_stub_gen_derive::{gen_stub_pyclass, gen_stub_pymethods};
 
 use crate::io::nvtiff::CudaCogReader;
 use crate::python::adapters::path_to_stream;
+use crate::traits::Transform;
 
 /// Python class interface to a Cloud-optimized GeoTIFF reader (nvTIFF backend) that
 /// decodes to GPU (CUDA) memory.
@@ -228,6 +230,30 @@ impl PyCudaCogReader {
     fn __dlpack_device__(&self) -> (i32, i32) {
         (self.device.device_type as i32, self.device.device_id)
     }
+
+    /// Get list of x and y coordinates.
+    ///
+    /// Determined based on an Affine transformation matrix built from the
+    /// `ModelPixelScaleTag` and `ModelTiepointTag` TIFF tags. Note that non-zero
+    /// rotation (set by `ModelTransformationTag`) is currently unsupported.
+    ///
+    /// Returns
+    /// -------
+    /// coords : (numpy.ndarray, numpy.ndarray)
+    ///     A tuple (x_coords, y_coords) of numpy.ndarray objects representing the
+    ///     GeoTIFF's x- and y-coordinates.
+    #[allow(clippy::type_complexity)]
+    fn xy_coords<'py>(
+        &self,
+        py: Python<'py>,
+    ) -> PyResult<(Bound<'py, PyArray1<f64>>, Bound<'py, PyArray1<f64>>)> {
+        let (x_coords, y_coords) = self
+            .inner
+            .xy_coords()
+            .map_err(|err| PyValueError::new_err(err.frame().to_string()))?;
+
+        Ok((x_coords.to_pyarray(py), y_coords.to_pyarray(py)))
+    }
 }
 
 // Define a function to gather stub information.