Add D-inf and MFD variants of flow_path, watershed, and HAND#1020
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brendancol merged 6 commits intomasterfrom Mar 17, 2026
Merged
Add D-inf and MFD variants of flow_path, watershed, and HAND#1020brendancol merged 6 commits intomasterfrom
brendancol merged 6 commits intomasterfrom
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Implements six new hydrology modules, each with four backends (numpy, cupy, dask, dask+cupy) and full test coverage: - flow_path_dinf: D-inf flow path tracing (dominant neighbor) - flow_path_mfd: MFD flow path tracing (dominant neighbor) - watershed_dinf: D-inf watershed delineation - watershed_mfd: MFD watershed delineation - hand_dinf: D-inf Height Above Nearest Drainage - hand_mfd: MFD Height Above Nearest Drainage Closes #1014, closes #1015, closes #1016, closes #1017, closes #1018, closes #1019
Moves 30 hydrology source modules and 30 test files into xrspatial/hydrology/ and xrspatial/hydrology/tests/ respectively. Also moves _boundary_store.py which is used exclusively by hydrology code. All internal cross-references updated. Top-level imports (from xrspatial import flow_direction, etc.) still work via xrspatial/__init__.py re-exports. The new xrspatial.hydrology subpackage also provides direct access (from xrspatial.hydrology import flow_direction). 457 hydrology tests pass, 2050 non-hydrology tests pass.
Rename all 13 unsuffixed D8 source files and their test files to include a _d8 suffix (e.g. flow_direction.py -> flow_direction_d8.py), matching the existing _dinf/_mfd convention. Public functions inside each file are also renamed (flow_direction -> flow_direction_d8, etc.). stream_order_d8's "method" parameter (strahler/shreve) is renamed to "ordering" to avoid collision with the routing dispatch. hydro/__init__.py now provides unified wrappers via _RoutingDispatch, so callers can do flow_direction(dem, routing='dinf') instead of importing flow_direction_dinf directly. D8-only functions (basin, sink, fill, twi, snap_pour_point) accept routing= for forward compatibility. All cross-module imports, dinf/mfd helper imports, test imports, and example imports are updated accordingly.
The cross-backend tests parametrize size and dtype for the random_data fixture but the test functions didn't declare those parameters, causing pytest collection to fail.
The random_data fixture lives in xrspatial/tests/conftest.py, which pytest can't discover from xrspatial/hydro/tests/. Re-export it so the flow_direction cross-backend parametrized tests can find it.
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Summary
Each module supports all four backends (numpy, cupy, dask, dask+cupy) and follows the same architecture as the existing D8 implementations. The D-inf variants use angle decomposition from
_angle_to_neighbors; the MFD variants follow the highest-fraction neighbor at each step.Six new modules, 84 new tests, all passing. No changes to existing modules or tests.
Test plan
pytest xrspatial/tests/test_{flow_path,watershed,hand}_{dinf,mfd}.py)Closes #1014, closes #1015, closes #1016, closes #1017, closes #1018, closes #1019