def test_dem_subtraction():
"""Test that the DEM subtraction script gives reasonable numbers."""
with warnings.catch_warnings():
warnings.filterwarnings("ignore", category=DeprecationWarning)
diff = xdem.spatial_tools.subtract_rasters(
examples.get_path("longyearbyen_ref_dem"),
examples.get_path("longyearbyen_tba_dem"))
assert np.nanmean(np.abs(diff.data)) < 100
def load_ref_and_diff() -> tuple[gu.georaster.Raster, gu.georaster.Raster, np.ndarray]:
"""Load example files to try coregistration methods with."""
reference_raster = gu.georaster.Raster(examples.get_path("longyearbyen_ref_dem"))
glacier_mask = gu.geovector.Vector(examples.get_path("longyearbyen_glacier_outlines"))
ddem = gu.georaster.Raster(examples.get_path('longyearbyen_ddem'))
mask = glacier_mask.create_mask(ddem)
return reference_raster, ddem, mask
def load_examples(
) -> tuple[gu.georaster.Raster, gu.georaster.Raster, gu.geovector.Vector]:
"""Load example files to try coregistration methods with."""
with warnings.catch_warnings():
warnings.simplefilter("ignore")
reference_raster = gu.georaster.Raster(
examples.get_path("longyearbyen_ref_dem"))
to_be_aligned_raster = gu.georaster.Raster(
examples.get_path("longyearbyen_tba_dem"))
glacier_mask = gu.geovector.Vector(
examples.get_path("longyearbyen_glacier_outlines"))
return reference_raster, to_be_aligned_raster, glacier_mask
class TestMerging:
"""
Test cases for stacking and merging DEMs
Split a DEM with some overlap, then stack/merge it, and validate bounds and shape.
"""
dem = gu.georaster.Raster(examples.get_path("longyearbyen_ref_dem"))
# Find the easting midpoint of the DEM
x_midpoint = np.mean([dem.bounds.right, dem.bounds.left])
x_midpoint -= x_midpoint % dem.res[0]
# Cut the DEM into two DEMs that slightly overlap each other.
dem1 = dem.copy()
dem1.crop(
rio.coords.BoundingBox(
right=x_midpoint + dem.res[0] * 3, left=dem.bounds.left, top=dem.bounds.top, bottom=dem.bounds.bottom
)
)
dem2 = dem.copy()
dem2.crop(
rio.coords.BoundingBox(
left=x_midpoint - dem.res[0] * 3, right=dem.bounds.right, top=dem.bounds.top, bottom=dem.bounds.bottom
)
)
# To check that use_ref_bounds work - create a DEM that do not cover the whole extent
dem3 = dem.copy()
dem3.crop(
rio.coords.BoundingBox(
left=x_midpoint - dem.res[0] * 3,
right=dem.bounds.right - dem.res[0] * 2,
top=dem.bounds.top,
bottom=dem.bounds.bottom,
)
)
def test_stack_rasters(self):
"""Test stack_rasters"""
# Merge the two overlapping DEMs and check that output bounds and shape is correct
stacked_dem = xdem.spatial_tools.stack_rasters([self.dem1, self.dem2])
assert stacked_dem.count == 2
assert self.dem.shape == stacked_dem.shape
merged_bounds = xdem.spatial_tools.merge_bounding_boxes(
[self.dem1.bounds, self.dem2.bounds], resolution=self.dem1.res[0]
)
assert merged_bounds == stacked_dem.bounds
# Check that reference works with input Raster
stacked_dem = xdem.spatial_tools.stack_rasters([self.dem1, self.dem2], reference=self.dem)
assert self.dem.bounds == stacked_dem.bounds
# Others than int or gu.Raster should raise a ValueError
try:
stacked_dem = xdem.spatial_tools.stack_rasters([self.dem1, self.dem2], reference="a string")
except ValueError as exception:
if "reference should be" not in str(exception):
raise exception
# Check that use_ref_bounds works - use a DEM that do not cover the whole extent
# This case should not preserve original extent
stacked_dem = xdem.spatial_tools.stack_rasters([self.dem1, self.dem3])
assert stacked_dem.bounds != self.dem.bounds
# This case should preserve original extent
stacked_dem2 = xdem.spatial_tools.stack_rasters([self.dem1, self.dem3], reference=self.dem, use_ref_bounds=True)
assert stacked_dem2.bounds == self.dem.bounds
def test_merge_rasters(self):
"""Test merge_rasters"""
# Merge the two overlapping DEMs and check that it closely resembles the initial DEM
merged_dem = xdem.spatial_tools.merge_rasters([self.dem1, self.dem2])
assert self.dem.data.shape == merged_dem.data.shape
assert self.dem.bounds == merged_dem.bounds
diff = self.dem.data - merged_dem.data
assert np.abs(np.nanmean(diff)) < 0.0001
# Check that reference works
merged_dem2 = xdem.spatial_tools.merge_rasters([self.dem1, self.dem2], reference=self.dem)
assert merged_dem2 == merged_dem