fix: construct resample transform from exact target cell size - #440
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nathanjmcdougall merged 1 commit intoMay 5, 2026
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Raster.resample() now produces output cells with the exact requested cell size, fixing drift that caused downstream NonSquareCellsError. Background: - The original implementation (63355c4, 2025-08-13) computed the output transform via dataset.transform.scale(width/new_width, height/new_height), which introduces rounding error when np.ceil rounds the array dimensions. This was masked by a stored cell_size field on RasterMeta that acted as the source of truth regardless of what the transform said. - In aa699db (2026-02-18), cell_size was refactored from a stored field to a derived property (abs(transform.a)), but the transform computation was left unchanged. The compensating mechanism was removed without fixing the underlying calculation, exposing the drift. - Existing tests never caught this because their fixtures use dimensions (4x4, 2x2) and ratios (x2, /2) where ceil produces exact integers. Fix: construct the Affine transform directly from the target cell size, preserving the original origin. The ceil-rounded array dimensions still ensure full extent coverage, but the metadata is now truthful. Closes #438
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May 5, 2026 00:22
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Raster.resample() now produces output cells with the exact requested cell size, fixing drift that caused downstream NonSquareCellsError.
Background:
Fix: construct the Affine transform directly from the target cell size, preserving the original origin. The ceil-rounded array dimensions still ensure full extent coverage, but the metadata is now truthful.
Closes #438