geotiff: fix stripped-GPU windowed coords on non-georef TIFFs (#1753)

.claude/sweep-metadata-state.csv

@@ -1,4 +1,3 @@
 module,last_inspected,issue,severity_max,categories_found,notes
-geotiff,2026-05-12,1710,MEDIUM,2,"open_geotiff/read_geotiff_dask/read_geotiff_gpu windowed reads of non-georef TIFFs produced float64 half-pixel-shifted coords while full reads produced int64 [0,1,2,...] coords. Affected every backend the same way; not a backend parity bug, a windowed-vs-full inconsistency. _populate_attrs_from_geo_info also fabricated an identity transform attr on non-georef files. Fixed by threading has_georef through all windowed coord paths and through the transform attr emitter (#1710)."
-geotiff,2026-05-12,1739,HIGH,1;4,"COG overview reads dropped attrs['nodata'] from level 0, so the writer-baked sentinel survived as raw data in the overview pixels (silent numerical corruption). extract_geo_info_with_overview_inheritance was inheriting CRS-side fields only; extended to per-IFD pass-through tags (nodata, gdal_metadata*, resolution*, colormap, extra_tags, image_description, extra_samples). All four backends affected (numpy/dask/cupy/dask+cupy). Fixed in #1739."
+geotiff,2026-05-12,1753,HIGH,2,"read_geotiff_gpu stripped-fallback windowed read on a non-georef TIFF emitted float64 [-0.5, -1.5, ...] coords via the default unit GeoTransform placeholder, while the eager numpy and dask paths emit int64 file-relative pixel coords. Regression of #1710 (fix missed the stripped GPU branch). The tiled-GPU helper _gpu_apply_window_band already gates on has_georef correctly; the stripped fallback only checked t is None. Fixed by routing both non-georef and t-is-None cases through the integer pixel-coord branch and using file-relative offsets to match every other backend. Verified 4-backend parity (numpy / cupy / dask+numpy / dask+cupy)."
 reproject,2026-05-10,1572;1573,HIGH,1;3;4,geoid_height_raster dropped input attrs and used dims[-2:] for 3D inputs (#1572). reproject/merge ignored nodatavals (rasterio convention) when rioxarray absent (#1573). Fixed in same branch.

xrspatial/geotiff/__init__.py

@@ -2720,14 +2720,21 @@ def read_geotiff_gpu(source: str, *,
                 arr_gpu = arr_gpu.astype(target)
             # ``read_to_array`` already applied window + band slicing, so
             # ``arr_gpu`` is at output shape. Compute coords for that
-            # shape without re-slicing.
+            # shape without re-slicing. Mirror the eager-numpy /
+            # ``read_geotiff_dask`` / ``_gpu_apply_window_band`` checks
+            # against ``has_georef``: a non-georef TIFF carries a
+            # default ``GeoTransform()`` placeholder (``t is None`` is
+            # never true here) so a transform-based coord path would
+            # emit synthetic ``[-0.5, -1.5, ...]`` floats instead of
+            # the integer pixel coords every other backend produces
+            # (#1753 / regression of #1710).
             if window is not None:
                 r0, c0, r1, c1 = window
                 t = geo_info.transform
-                if t is None:
+                if t is None or not getattr(geo_info, 'has_georef', True):
                     coords = {
-                        'y': np.arange(r1 - r0, dtype=np.int64),
-                        'x': np.arange(c1 - c0, dtype=np.int64),
+                        'y': np.arange(r0, r1, dtype=np.int64),
+                        'x': np.arange(c0, c1, dtype=np.int64),
                     }
                 elif geo_info.raster_type == RASTER_PIXEL_IS_POINT:
                     coords = {

xrspatial/geotiff/tests/test_no_georef_windowed_coords_1710.py

@@ -119,6 +119,34 @@ def test_dask_cupy_windowed_integer_coords(self, no_georef_path_1710):
         assert da.y.dtype == np.int64
         np.testing.assert_array_equal(da.y.values, np.arange(4))
 
+    def test_offset_window_integer_coords(self, no_georef_path_1710):
+        """GPU windowed read at a non-zero origin: the stripped-GPU
+        fallback in ``read_geotiff_gpu`` checked ``t is None`` instead
+        of ``has_georef`` (issue #1753 / regression of #1710), so a
+        non-georef TIFF emitted ``[-0.5, -1.5, ...]`` via the unit
+        ``GeoTransform`` placeholder. Pin the contract that the offset
+        window produces file-relative integer coords identical to the
+        eager numpy path.
+        """
+        da = open_geotiff(no_georef_path_1710, gpu=True,
+                          window=(2, 3, 6, 7))
+        assert da.y.dtype == np.int64
+        assert da.x.dtype == np.int64
+        np.testing.assert_array_equal(da.y.values, np.arange(2, 6))
+        np.testing.assert_array_equal(da.x.values, np.arange(3, 7))
+
+    def test_offset_window_no_transform_attr(self, no_georef_path_1710):
+        """Non-georef GPU windowed read still must not advertise a
+        fabricated ``attrs['transform']`` -- ``_populate_attrs_from_geo_info``
+        gates on ``has_georef`` too, so flag the round-trip here.
+        """
+        da = open_geotiff(no_georef_path_1710, gpu=True,
+                          window=(2, 3, 6, 7))
+        assert 'transform' not in da.attrs, (
+            f"non-georef GPU windowed read should not carry a "
+            f"fabricated transform; got attrs={dict(da.attrs)}"
+        )
+
 
 class TestBackendParity:
     """Full read and windowed read must agree on coord dtype and values