[XARRAY] add env settings to fallback to WGS84 when no CRS is provided

CHANGES.md

@@ -1,5 +1,6 @@
 # unreleased
 
+* add `RIO_TILER_XARRAY_DEFAULT_WGS84=TRUE/FALSE` environment variable to enable setting WGS84 CRS by default when no CRS is provided in Xarray dataset
 * better error message for `TileOutsideBounds` errors (author @abarciauskas-bgse, https://github.com/cogeotiff/rio-tiler/pull/712)
 * handle of inverted latitude in `reader.point` (author @georgespill, https://github.com/cogeotiff/rio-tiler/pull/716)
 

docs/src/readers.md

@@ -1179,4 +1179,8 @@ print(info.json(exclude_none=True))
 !!! Important
 
     Not Implemented
-```
+
+
+#### Settings
+
+`RIO_TILER_XARRAY_DEFAULT_WGS84=TRUE/FALSE` environment variable can be used to enable setting `WGS84` CRS by default when the CRS information is not defined in the Xarray dataset. Defaults to `False`.

rio_tiler/errors.py

@@ -83,3 +83,11 @@ class AssetAsBandError(RioTilerError):
 
 class InvalidPointDataError(RioTilerError):
     """Invalid PointData."""
+
+
+class MissingCRSWarning(UserWarning):
+    """Missing CRS information."""
+
+
+class OverwritingCRSWarning(UserWarning):
+    """Overwriting CRS information."""

rio_tiler/io/xarray.py

@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+import os
 import warnings
 from typing import Any, Dict, List, Optional
 
@@ -15,7 +16,12 @@
 from rasterio.warp import transform as transform_coords
 
 from rio_tiler.constants import WEB_MERCATOR_TMS, WGS84_CRS
-from rio_tiler.errors import PointOutsideBounds, TileOutsideBounds
+from rio_tiler.errors import (
+    MissingCRSWarning,
+    OverwritingCRSWarning,
+    PointOutsideBounds,
+    TileOutsideBounds,
+)
 from rio_tiler.io.base import BaseReader
 from rio_tiler.models import BandStatistics, ImageData, Info, PointData
 from rio_tiler.types import BBox, NoData, WarpResampling
@@ -32,6 +38,11 @@
     rioxarray = None  # type: ignore
 
 
+default_to_wgs84_crs = os.environ.get(
+    "RIO_TILER_XARRAY_DEFAULT_WGS84", "FALSE"
+).upper() in ["TRUE", "YES"]
+
+
 @attr.s
 class XarrayReader(BaseReader):
     """Xarray Reader.
@@ -71,7 +82,20 @@ def __attrs_post_init__(self):
         assert rioxarray is not None, "rioxarray must be installed to use XarrayReader"
 
         self.bounds = tuple(self.input.rio.bounds())
+
+        if not self.input.rio.crs and default_to_wgs84_crs:
+            warnings.warn(
+                "Dataset doesn't have a valid CRS set. Automatically setting CRS to WGS84",
+                OverwritingCRSWarning,
+            )
+            self.input.rio.write_crs("epsg:4326", inplace=True)
+
         self.crs = self.input.rio.crs
+        if not self.crs:
+            warnings.warn(
+                "Dataset doesn't have a valid CRS set. rio-tiler might not work properly",
+                MissingCRSWarning,
+            )
 
         self._dims = [
             d

tests/test_io_xarray.py

@@ -1,13 +1,15 @@
 """tests rio_tiler.io.xarray.XarrayReader"""
 
 from datetime import datetime
+from unittest.mock import patch
 
 import morecantile
 import numpy
 import pytest
 import rioxarray
 import xarray
 
+from rio_tiler.errors import MissingCRSWarning, OverwritingCRSWarning
 from rio_tiler.io import XarrayReader
 
 
@@ -321,3 +323,51 @@ def test_xarray_reader_resampling():
 
         with pytest.warns(DeprecationWarning):
             _ = dst.feature(feat, resampling_method="nearest")
+
+
+@patch("rio_tiler.io.xarray.default_to_wgs84_crs", new=True)
+def test_xarray_reader_default_crs():
+    """Should raise OverwritingCRSWarning warning."""
+    arr = numpy.arange(0.0, 33 * 35).reshape(1, 33, 35)
+    data = xarray.DataArray(
+        arr,
+        dims=("time", "y", "x"),
+        coords={
+            "x": list(range(-170, 180, 10)),
+            "y": list(range(-80, 85, 5)),
+            "time": [datetime(2022, 1, 1)],
+        },
+    )
+    data.attrs.update({"valid_min": arr.min(), "valid_max": arr.max()})
+
+    with pytest.warns(OverwritingCRSWarning):
+        with XarrayReader(data) as dst:
+            info = dst.info()
+            assert info.minzoom == 0
+            assert info.maxzoom == 0
+            assert info.band_metadata == [("b1", {})]
+            assert info.band_descriptions == [("b1", "2022-01-01T00:00:00.000000000")]
+            assert info.height == 33
+            assert info.width == 35
+            assert info.count == 1
+            assert info.attrs
+
+
+@patch("rio_tiler.io.xarray.default_to_wgs84_crs", new=False)
+def test_xarray_reader_no_default_crs():
+    """Should raise MissingCRSWarning warning."""
+    arr = numpy.arange(0.0, 33 * 35).reshape(1, 33, 35)
+    data = xarray.DataArray(
+        arr,
+        dims=("time", "y", "x"),
+        coords={
+            "x": list(range(-170, 180, 10)),
+            "y": list(range(-80, 85, 5)),
+            "time": [datetime(2022, 1, 1)],
+        },
+    )
+    data.attrs.update({"valid_min": arr.min(), "valid_max": arr.max()})
+
+    with pytest.warns(MissingCRSWarning):
+        with XarrayReader(data) as dst:
+            assert dst.info()