fix: gridarea handles projected-CRS inputs#51
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sibrenloos merged 1 commit intoJun 3, 2026
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raster_utils._reggrid_area assumes lat/lon in degrees; when fed projected coordinates in metres (SVY21, Mollweide, ...) sin(radians(Northing)) returns partly-negative cell areas. This silently corrupts: - mm -> m3/s hydrology forcing conversion (flips precip sign) - setup_emission_raster with area_division=True (banded artefacts) Fix: branch on crs.is_projected and delegate to ds.raster.area_grid().
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fix tested succesfully, area grid is correct and resolved issues with other conversions using area grid |
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Jun 3, 2026
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succesfully tested for WGS84 and EPSG:3414 testcase
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workflows.emissions.gridareacalledraster_utils._reggrid_areaunconditionally. That helper is a spherical-cap calculation assuming lat/lon in degrees but for projected-CRS inputs in metres (SVY21/ EPSG:3414, ESRI:54009 Mollweide, etc.)sin(radians(Northing))of large angles returns partly-negative, periodic values silently corrupting downstream.Problem manifested in:
workflows.forcing.hydrology_forcing_emmultiplies a corrupted area calculation resulting in negative precipitation indynamicdata.nc/hydrology.binarea_division=Truegoing from projected to reprojected, an interleaving pattern, banding with negative values, is observed. Noted in Negative values in emission maps #20 and worsened by going from one projected crs to another, where ghs_pop_2015 had negative values and banding.Fix
gridareato handle projected crsadd regression test