Fix metadata propagation in reproject (#1572, #1573)#1575
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brendancol merged 1 commit intomainfrom May 11, 2026
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geoid_height_raster previously dropped all input attrs and used
raster.dims[-2:] as the output dims. The latter produced garbage for
3D (y, x, band) rasters: the output came out shaped (4, 3) with dims
('x', 'band') instead of (4, 4) with dims ('y', 'x'). Use
_find_spatial_dims so the y/x axes are resolved regardless of layout,
and carry input attrs forward so crs / res / transform survive.
reproject and merge previously ignored attrs['nodatavals'] (rasterio's
plural convention) unless rioxarray happened to be installed and its
accessor picked it up. Without rioxarray, a raster carrying only
nodatavals was treated as if nodata was NaN, so the sentinel pixels
silently survived resampling. _detect_nodata now consults nodatavals
after _FillValue / nodata / missing_value, and the output keeps the
nodatavals tuple consistent with the resolved nodata.
Tests cover both bugs across 2D and 3D inputs and verify attrs
survive on numpy, dask, cupy, and dask+cupy backends.
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Pull request overview
This PR fixes two metadata propagation issues in xrspatial.reproject: (1) geoid_height_raster now correctly identifies spatial dimensions for 3D rasters and preserves input attributes, and (2) nodata detection/propagation now honors the rasterio attrs['nodatavals'] convention and keeps nodata/nodatavals consistent after reproject()/merge().
Changes:
- Update
geoid_height_rasterto resolve(y, x)dims via_find_spatial_dims, always return a 2D(y, x)output, and carry forward inputattrswithunits/modellayered on top. - Extend
_detect_nodatato consultattrs['nodatavals'](tuple/scalar) when other nodata keys are absent. - Refresh output
attrs['nodatavals']inreproject()andmerge()to match the resolved output nodata sentinel, and add regression tests for both issues.
Reviewed changes
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Show a summary per file
| File | Description |
|---|---|
xrspatial/tests/test_reproject.py |
Adds regression tests for nodatavals handling in reproject/merge and for metadata + 3D→2D behavior in geoid_height_raster. |
xrspatial/reproject/_vertical.py |
Fixes geoid_height_raster spatial-dim resolution for 3D inputs and preserves input attrs on output. |
xrspatial/reproject/_crs_utils.py |
Adds attrs['nodatavals'] to the nodata detection fallback chain. |
xrspatial/reproject/__init__.py |
Ensures reproject()/merge() refresh attrs['nodatavals'] to match the resolved nodata. |
.claude/sweep-metadata-state.csv |
Updates internal sweep tracking metadata for the inspected module/issues. |
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Summary
geoid_height_rasternow carries input attrs forward and resolves the y/x dims via_find_spatial_dims, so 3D (y, x, band) rasters reduce to a correct 2D output (closes geoid_height_raster drops input attrs and mishandles 3D rasters #1572)._detect_nodataconsultsattrs['nodatavals'](rasterio plural convention) after the singular keys, andreproject/mergerefresh thenodatavalstuple to match the resolved nodata so the two attrs no longer disagree (closes reproject ignores attrs['nodatavals'] when rioxarray is not installed #1573).Before this change, a
(y, x, band)-shaped raster passed togeoid_height_rasterproduced a 2D output labelled('x', 'band')with the wrong shape and the wrong coords (becauseraster.dims[-2:]for a(y, x, band)input is('x', 'band')). Input attrs likecrs,res,transform,_FillValue,long_namewere also dropped.Without rioxarray installed, a raster carrying only
attrs['nodatavals'] = (-9999,)would be treated by reproject as if nodata was NaN, so the -9999 pixels survived resampling unmasked while the output still carried a stalenodatavals=(-9999,)attr alongside a freshnodata=NaN.xrspatial.resamplealready handlesnodatavals, so the inconsistency was local to reproject.Test plan
pytest xrspatial/tests/test_reproject.py-- 200 passing including 9 new metadata testsattrs['nodata']andattrs['nodatavals']agree on output for all four paths(y, x, band)input togeoid_height_rasterreturns a 2D(y, x)array with inputcrspreservedpytest xrspatial/tests/test_resample.py-- 169 passing (no regressions from the shared_detect_nodatachange)Found during deep-sweep / metadata pass on the reproject module.