Bugfix shape masking

lib/iris/tests/unit/_shapefiles/__init__.py

@@ -0,0 +1,5 @@
+# Copyright Iris contributors
+#
+# This file is part of Iris and is released under the BSD license.
+# See LICENSE in the root of the repository for full licensing details.
+"""Unit tests for the :mod:`iris._shapefiles` module."""

lib/iris/tests/unit/_shapefiles/test_is_geometry_valid.py

@@ -0,0 +1,189 @@
+# Copyright Iris contributors
+#
+# This file is part of Iris and is released under the BSD license.
+# See LICENSE in the root of the repository for full licensing details.
+"""Unit tests for :func:`iris._shapefiles.is_geometry_valid`."""
+
+# import iris tests first so that some things can be initialised before
+# importing anything else
+import iris.tests as tests  # isort:skip
+
+from pyproj import CRS
+import pytest
+from shapely.geometry import (
+    LineString,
+    MultiLineString,
+    MultiPoint,
+    MultiPolygon,
+    Point,
+    box,
+)
+
+from iris._shapefiles import is_geometry_valid
+
+
+# Shareable shape fixtures used in:
+# - util/test_mask_cube_from_shapefile.py
+# - _shapefiles/test_is_geometry_valid.py
+@pytest.fixture(scope="session")
+def wgs84_crs():
+    return CRS.from_epsg(4326)
+
+
+@pytest.fixture(scope="session")
+def osgb_crs():
+    return CRS.from_epsg(27700)
+
+
+@pytest.fixture(scope="session")
+def basic_polygon_geometry():
+    # Define the coordinates of a basic rectangle
+    min_lon = -90
+    min_lat = -45
+    max_lon = 90
+    max_lat = 45
+
+    # Create the rectangular geometry
+    return box(min_lon, min_lat, max_lon, max_lat)
+
+
+@pytest.fixture(scope="session")
+def basic_multipolygon_geometry():
+    # Define the coordinates of a basic rectangle
+    min_lon = 0
+    min_lat = 0
+    max_lon = 8
+    max_lat = 8
+
+    # Create the rectangular geometry
+    return MultiPolygon(
+        [
+            box(min_lon, min_lat, max_lon, max_lat),
+            box(min_lon + 10, min_lat + 10, max_lon + 10, max_lat + 10),
+        ]
+    )
+
+
+@pytest.fixture(scope="session")
+def basic_point_geometry():
+    # Define the coordinates of a basic point (lon, lat)
+    return Point((-3.476204, 50.727059))
+
+
+@pytest.fixture(scope="session")
+def basic_line_geometry():
+    # Define the coordinates of a basic line
+    return LineString([(0, 0), (10, 10)])
+
+
+@pytest.fixture(scope="session")
+def basic_multiline_geometry():
+    # Define the coordinates of a basic line
+    return MultiLineString([[(0, 0), (10, 10)], [(20, 20), (30, 30)]])
+
+
+@pytest.fixture(scope="session")
+def basic_point_collection():
+    # Define the coordinates of a basic collection of points
+    # as (lon, lat) tuples, assuming a WGS84 projection.
+    points = MultiPoint(
+        [
+            (0, 0),
+            (10, 10),
+            (-10, -10),
+            (-3.476204, 50.727059),
+            (174.761067, -36.846211),
+            (-77.032801, 38.892717),
+        ]
+    )
+
+    return points
+
+
+@pytest.fixture(scope="session")
+def canada_geometry():
+    # Define the coordinates of a rectangle that covers Canada
+    return box(-143.5, 42.6, -37.8, 84.0)
+
+
+@pytest.fixture(scope="session")
+def bering_sea_geometry():
+    # Define the coordinates of a rectangle that covers the Bering Sea
+    return box(148.42, 49.1, -138.74, 73.12)
+
+
+@pytest.fixture(scope="session")
+def uk_geometry():
+    # Define the coordinates of a rectangle that covers the UK
+    return box(-10, 49, 2, 61)
+
+
+@pytest.fixture(scope="session")
+def invalid_geometry_poles():
+    # Define the coordinates of a rectangle that crosses the poles
+    return box(-10, -90, 10, 90)
+
+
+@pytest.fixture(scope="session")
+def invalid_geometry_bounds():
+    # Define the coordinates of a rectangle that is outside the bounds of the coordinate system
+    return box(-200, -100, 200, 100)
+
+
+@pytest.fixture(scope="session")
+def not_a_valid_geometry():
+    # Return an invalid geometry type
+    # This is not a valid geometry, e.g., a string
+    return "This is not a valid geometry"
+
+
+# Test validity of different geometries
+@pytest.mark.parametrize(
+    "test_input",
+    [
+        "basic_polygon_geometry",
+        "basic_multipolygon_geometry",
+        "basic_point_geometry",
+        "basic_point_collection",
+        "basic_line_geometry",
+        "basic_multiline_geometry",
+        "canada_geometry",
+    ],
+)
+def test_valid_geometry(test_input, request, wgs84_crs):
+    # Assert that all valid geometries are return None
+    assert is_geometry_valid(request.getfixturevalue(test_input), wgs84_crs) is None
+
+
+# Fixtures retrieved from conftest.py
+# N.B. error message comparison is done with regex so
+# any parentheses in the error message must be escaped (\)
+@pytest.mark.parametrize(
+    "test_input, errortype, errormessage",
+    [
+        (
+            "bering_sea_geometry",
+            ValueError,
+            "Geometry crossing the antimeridian is not supported.",
+        ),
+        (
+            "invalid_geometry_poles",
+            ValueError,
+            "Geometry crossing the poles is not supported.",
+        ),
+        (
+            "invalid_geometry_bounds",
+            ValueError,
+            r"Geometry \[<POLYGON \(\(200 -100, 200 100, -200 100, -200 -100, 200 -100\)\)>\] is not valid for the given coordinate system EPSG:4326. \nCheck that your coordinates are correctly specified.",
+        ),
+        (
+            "not_a_valid_geometry",
+            TypeError,
+            r"Shape geometry is not a valid shape \(not well formed\).",
+        ),
+    ],
+)
+def test_invalid_geometry(test_input, errortype, errormessage, request, wgs84_crs):
+    # Assert that all invalid geometries raise the expected error
+    with pytest.raises(errortype, match=errormessage):
+        is_geometry_valid(request.getfixturevalue(test_input), wgs84_crs)

lib/iris/tests/unit/_shapefiles/test_transform_geometry.py

@@ -0,0 +1,100 @@
+from pyproj import CRS
+from pyproj import exceptions as pyproj_exceptions
+import pytest
+import shapely
+from shapely.geometry import LineString, MultiLineString, MultiPoint, Point, Polygon
+
+import iris
+from iris._shapefiles import _transform_geometry
+from iris.tests import _shared_utils, stock
+
+wgs84 = CRS.from_epsg(4326)  # WGS84 coordinate system
+osgb = CRS.from_epsg(27700)  # OSGB coordinate system
+
+
+@pytest.mark.parametrize(
+    "input_geometry, input_geometry_crs, input_cube_crs, output_expected_geometry",
+    [
+        (  # Basic geometry in WGS84, no transformation needed
+            shapely.geometry.box(-10, 50, 2, 60),
+            wgs84,
+            stock.simple_pp().coord_system()._crs,
+            shapely.geometry.box(-10, 50, 2, 60),
+        ),
+        (  # Basic geometry in WGS84, transformed to OSGB
+            shapely.geometry.box(-10, 50, 2, 60),
+            wgs84,
+            iris.load_cube(
+                _shared_utils.get_data_path(
+                    ("NetCDF", "transverse_mercator", "tmean_1910_1910.nc")
+                )
+            )
+            .coord_system()
+            .as_cartopy_projection(),
+            Polygon(
+                [
+                    (686600.5247600826, 18834.835866007765),
+                    (622998.2965261643, 1130592.5248690124),
+                    (-45450.063023168186, 1150844.9676151862),
+                    (-172954.59474739246, 41898.60193228102),
+                    (686600.5247600826, 18834.835866007765),
+                ]
+            ),
+        ),
+        (  # Basic geometry in WGS84, no transformation needed
+            LineString([(-10, 50), (2, 60)]),
+            wgs84,
+            stock.simple_pp().coord_system()._crs,
+            LineString([(-10, 50), (2, 60)]),
+        ),
+        (  # Basic geometry in WGS84, no transformation needed
+            Point((-10, 50)),
+            wgs84,
+            stock.simple_pp().coord_system()._crs,
+            Point((-10, 50)),
+        ),
+    ],
+)
+def test_transform_geometry(
+    input_geometry,
+    input_geometry_crs,
+    input_cube_crs,
+    output_expected_geometry,
+):
+    # Assert that all invalid geometries raise the expected error
+    out_geometry = _transform_geometry(
+        input_geometry, input_geometry_crs, input_cube_crs
+    )
+    assert isinstance(out_geometry, shapely.geometry.base.BaseGeometry)
+    assert output_expected_geometry == out_geometry
+
+
+# Assert that an invalid inputs raise the expected errors
+@pytest.mark.parametrize(
+    "input_geometry, input_geometry_crs, input_cube_crs, expected_error",
+    [
+        (  # Basic geometry in WGS84, no transformation needed
+            "bad_input_geometry",
+            wgs84,
+            stock.simple_pp().coord_system()._crs,
+            AttributeError,
+        ),
+        (  # Basic geometry in WGS84, no transformation needed
+            shapely.geometry.box(-10, 50, 2, 60),
+            "bad_input_crs",
+            stock.simple_pp().coord_system()._crs,
+            pyproj_exceptions.CRSError,
+        ),
+        (  # Basic geometry in WGS84, no transformation needed
+            shapely.geometry.box(-10, 50, 2, 60),
+            wgs84,
+            "bad_input_cube_crs",
+            pyproj_exceptions.CRSError,
+        ),
+    ],
+)
+def test_transform_geometry_invalid_input(
+    input_geometry, input_geometry_crs, input_cube_crs, expected_error
+):
+    with pytest.raises(expected_error):
+        _transform_geometry(input_geometry, input_geometry_crs, input_cube_crs)

lib/iris/tests/unit/conftest.py

@@ -4,6 +4,7 @@
 # See LICENSE in the root of the repository for full licensing details.
 """Unit tests fixture infra-structure."""
 
+from pyproj import CRS
 import pytest
 
 import iris