Fix choropleth horizontal line artifacts on projected maps#668
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cvanelteren merged 2 commits intoMar 30, 2026
mainUltraplot/UltraPlot:mainfrom
fix/choropleth-projection-artifactsUltraplot/UltraPlot:fix/choropleth-projection-artifactsCopy head branch name to clipboard
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Fix choropleth horizontal line artifacts on projected maps#668cvanelteren merged 2 commits intomainUltraplot/UltraPlot:mainfrom fix/choropleth-projection-artifactsUltraplot/UltraPlot:fix/choropleth-projection-artifactsCopy head branch name to clipboard
cvanelteren merged 2 commits into
mainUltraplot/UltraPlot:mainfrom
fix/choropleth-projection-artifactsUltraplot/UltraPlot:fix/choropleth-projection-artifactsCopy head branch name to clipboard
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Use Cartopy's project_geometry() instead of transform_points() for choropleth polygon projection. transform_points() projects vertices independently without geometric awareness, so polygons crossing the antimeridian (e.g. Russia) produce path segments that jump across the entire map, rendering as visible horizontal lines. project_geometry() properly splits and clips polygons at projection boundaries before converting to matplotlib paths, eliminating the artifacts on all projections (Robinson, Mercator, Mollweide, etc.).
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* Fix choropleth horizontal line artifacts on projected maps Use Cartopy's project_geometry() instead of transform_points() for choropleth polygon projection. transform_points() projects vertices independently without geometric awareness, so polygons crossing the antimeridian (e.g. Russia) produce path segments that jump across the entire map, rendering as visible horizontal lines. project_geometry() properly splits and clips polygons at projection boundaries before converting to matplotlib paths, eliminating the artifacts on all projections (Robinson, Mercator, Mollweide, etc.). * Black
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Fix an issue where choropleths were not rendering properly for anti-meridian plots.