v4.5.0a2

CHANGELOG.md

@@ -16,6 +16,14 @@ avoid adding features or APIs which do not map onto the
 
 ## Unreleased
 
+## [4.5.0a2] - 2026-02-27
+
+- `cells_to_h3shape`/`cells_to_geo` now handle all valid cell sets, including
+  sets that would produce global polygons crossing the antimeridian, poles, or are larger than a hemisphere
+  - Duplicate cells now raise `H3DuplicateInputError`
+  - Mixed-resolution cells now raise `H3ResMismatchError`
+  - Internal: switch from linked-list to array-based C API for cells-to-polygon conversion
+
 ## [4.5.0a1] - 2026-02-25
 
 - Update `h3lib` with draft v4.5 changes

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = 'scikit_build_core.build'
 
 [project]
 name = 'h3'
-version = '4.5.0a1'
+version = '4.5.0a2'
 description = "Uber's hierarchical hexagonal geospatial indexing system"
 readme = 'readme.md'
 license = {file = 'LICENSE'}

src/h3/_cy/h3lib.pxd

@@ -47,21 +47,6 @@ cdef extern from 'h3api.h':
         int i
         int j
 
-    ctypedef struct LinkedLatLng:
-        LatLng data 'vertex'
-        LinkedLatLng *next
-
-    # renaming these for clarity
-    ctypedef struct LinkedGeoLoop:
-        LinkedLatLng *data 'first'
-        LinkedLatLng *_data_last 'last'  # not needed in Cython bindings
-        LinkedGeoLoop *next
-
-    ctypedef struct LinkedGeoPolygon:
-        LinkedGeoLoop *data 'first'
-        LinkedGeoLoop *_data_last 'last'  # not needed in Cython bindings
-        LinkedGeoPolygon *next
-
     ctypedef struct GeoLoop:
         int numVerts
         LatLng *verts
@@ -171,18 +156,18 @@ cdef extern from 'h3api.h':
     double greatCircleDistanceKm(const LatLng *a, const LatLng *b) nogil
     double greatCircleDistanceM(const LatLng *a, const LatLng *b) nogil
 
-    H3Error cellsToLinkedMultiPolygon(const H3int *h3Set, const int numCells, LinkedGeoPolygon *out)
-    void destroyLinkedMultiPolygon(LinkedGeoPolygon *polygon)
+    H3Error cellsToMultiPolygon(const H3int *cells, const int64_t numCells, GeoMultiPolygon *out)
+    void destroyGeoMultiPolygon(GeoMultiPolygon *mpoly)
 
     H3Error maxPolygonToCellsSize(const GeoPolygon *geoPolygon, int res, uint32_t flags, uint64_t *count)
     H3Error polygonToCells(const GeoPolygon *geoPolygon, int res, uint32_t flags, H3int *out)
 
     H3Error maxPolygonToCellsSizeExperimental(const GeoPolygon *geoPolygon, int res, uint32_t flags, uint64_t *count)
     H3Error polygonToCellsExperimental(const GeoPolygon *geoPolygon, int res, uint32_t flags, uint64_t sz, H3int *out)
 
-    # ctypedef struct GeoMultiPolygon:
-    #     int numPolygons
-    #     GeoPolygon *polygons
+    ctypedef struct GeoMultiPolygon:
+        int numPolygons
+        GeoPolygon *polygons
 
     # int hexRange(H3int origin, int k, H3int *out)
 

src/h3/_cy/to_multipoly.pyx

@@ -4,60 +4,42 @@ from .util cimport check_cell, coord2deg
 from .error_system cimport check_for_error
 
 
-# todo: it's driving me crazy that these three functions are all essentially the same linked list walker...
-# grumble: no way to do iterators in with cdef functions!
-cdef walk_polys(const h3lib.LinkedGeoPolygon* L):
-    out = []
-    while L:
-        out += [walk_loops(L.data)]
-        L = L.next
+cdef _loop_to_list(const h3lib.GeoLoop *loop):
+    return [coord2deg(loop.verts[v]) for v in range(loop.numVerts)]
 
-    return out
-
-
-cdef walk_loops(const h3lib.LinkedGeoLoop* L):
-    out = []
-    while L:
-        out += [walk_coords(L.data)]
-        L = L.next
-
-    return out
 
+cdef _poly_to_lists(const h3lib.GeoPolygon *poly):
+    return (
+        [_loop_to_list(&poly.geoloop)]
+        + [_loop_to_list(&poly.holes[h]) for h in range(poly.numHoles)]
+    )
 
-cdef walk_coords(const h3lib.LinkedLatLng* L):
-    out = []
-    while L:
-        out += [coord2deg(L.data)]
-        L = L.next
-
-    return out
 
-# todo: tuples instead of lists?
 def _to_multi_polygon(const H3int[:] cells):
     cdef:
-        h3lib.LinkedGeoPolygon polygon
+        h3lib.GeoMultiPolygon mpoly
+        H3int cell
 
-    for h in cells:
-        check_cell(h)
+    for cell in cells:
+        check_cell(cell)
 
     check_for_error(
-        h3lib.cellsToLinkedMultiPolygon(&cells[0], len(cells), &polygon)
+        h3lib.cellsToMultiPolygon(&cells[0], len(cells), &mpoly)
     )
 
-    out = walk_polys(&polygon)
-
-    # we're still responsible for cleaning up the passed in `polygon`,
-    # but not a problem here, since it is stack allocated
-    h3lib.destroyLinkedMultiPolygon(&polygon)
+    try:
+        out = [
+            _poly_to_lists(&mpoly.polygons[p])
+            for p in range(mpoly.numPolygons)
+        ]
+    finally:
+        h3lib.destroyGeoMultiPolygon(&mpoly)
 
     return out
 
 
 def cells_to_multi_polygon(const H3int[:] cells):
-    # todo: gotta be a more elegant way to handle these...
     if len(cells) == 0:
         return []
 
-    multipoly = _to_multi_polygon(cells)
-
-    return multipoly
+    return _to_multi_polygon(cells)