BUG: Fix #2864 by adding the missing vrt parameters (#2865)

* BUG: Fix #2864 by adding the missing vrt parameters (transform, width, height)

* TEST: Add a test to demonstrate that #2864 is actually fixed by patch

* DOC: Add an entry corresponding to the patch in whats-new.rst

* STY: Conform to PEP 8

* TEST: Fix test imports and assert for the affine transform check

Author: jmichel-otb

doc/whats-new.rst

@@ -45,6 +45,8 @@ Bug fixes
   (e.g., ``swap_dims``, ``isel``, ``reindex``, ``[]``) (:issue:`2842`,
   :issue:`2856`).
   By `Stephan Hoyer <https://github.com/shoyer>`_.
+- open_rasterio() now supports rasterio.vrt.WarpedVRT with custom transform, width and height (:issue:`2864`).
+  By `Julien Michel <https://github.com/jmichel-otb>`_.
 
 .. _whats-new.0.12.0:
 

xarray/backends/rasterio_.py

@@ -224,6 +224,9 @@ def open_rasterio(filename, parse_coordinates=None, chunks=None, cache=None,
                           src_nodata=vrt.src_nodata,
                           dst_nodata=vrt.dst_nodata,
                           tolerance=vrt.tolerance,
+                          transform=vrt.transform,
+                          width=vrt.width,
+                          height=vrt.height,
                           warp_extras=vrt.warp_extras)
 
     if lock is None:

xarray/tests/test_backends.py

@@ -3350,6 +3350,33 @@ def test_rasterio_vrt(self):
                         assert actual_shape == expected_shape
                         assert expected_val.all() == actual_val.all()
 
+    def test_rasterio_vrt_with_transform_and_size(self):
+        # Test open_rasterio() support of WarpedVRT with transform, width and
+        # height (issue #2864)
+        import rasterio
+        from rasterio.warp import calculate_default_transform
+        from affine import Affine
+        with create_tmp_geotiff() as (tmp_file, expected):
+            with rasterio.open(tmp_file) as src:
+                # Estimate the transform, width and height
+                # for a change of resolution
+                # tmp_file initial res is (1000,2000) (default values)
+                trans, w, h = calculate_default_transform(
+                    src.crs, src.crs, src.width, src.height,
+                    resolution=500, *src.bounds)
+                with rasterio.vrt.WarpedVRT(src, transform=trans,
+                                            width=w, height=h) as vrt:
+                    expected_shape = (vrt.width, vrt.height)
+                    expected_res = vrt.res
+                    expected_transform = vrt.transform
+                    with xr.open_rasterio(vrt) as da:
+                        actual_shape = (da.sizes['x'], da.sizes['y'])
+                        actual_res = da.res
+                        actual_transform = Affine(*da.transform)
+                        assert actual_res == expected_res
+                        assert actual_shape == expected_shape
+                        assert actual_transform == expected_transform
+
     @network
     def test_rasterio_vrt_network(self):
         import rasterio