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DuckDB Extensions All extensions A5 Geospatial Index

Geometry Integration functions in the A5 Geospatial Index DuckDB extension

Function category

Geometry Integration

3 functions

Convert cells to and from DuckDB's built-in GEOMETRY type — no spatial extension dependency required to produce it. Turn a cell into its boundary polygon or center point, or cover an arbitrary point, line, or polygon geometry with cells.

a5_cell_to_geometry

Scalar function Geometry Integration
Signature
2 overloaded forms · click to inspect
Arguments (Positional)
Argument cell Type UBIGINT Mode Positional Description
Description

Returns an A5 cell as a POLYGON geometry of its boundary

1 Example 1 
SELECT a5_cell_to_geometry(a5_lonlat_to_cell(-122.4, 37.8, 5));

Output

a5_cell_to_geometry(a5_lonlat_to_cell(-122.4, 37.8, 5))
POLYGON ((-123.91841441068891 37.07072636323092, -123.07208493364055 36.93440251226853, -122.23003392974135 36.79239099498031, -121.39776711864215 36.97396218211518, -120.5617228138475 37.150588175283566, -120.90288444799262 37.727609112987, -121.24914021841249 38.30267874469804, -122.1294038096313 38.231723424706054, -123.00840835218185 38.15508109275352, -123.46729324681684 37.61361779528323, -123.91841441068891 37.07072636323092))
Related functions

a5_cell_to_point

Scalar function Geometry Integration
Signature
a5_cell_to_point(cell: UBIGINT) → GEOMETRY
Arguments (Positional)
Argument cell Type UBIGINT Mode Positional Description
Description

Returns the center of an A5 cell as a POINT geometry

1 Example 1 
SELECT a5_cell_to_point(a5_lonlat_to_cell(-122.4, 37.8, 5));

Output

a5_cell_to_point(a5_lonlat_to_cell(-122.4, 37.8, 5))
POINT (-122.1945267557461 37.499947342760166)
Related functions

a5_geometry_to_cells

Scalar function Geometry Integration
Signature
2 overloaded forms · click to inspect
Arguments (Positional)
Argument geom Type GEOMETRY Mode Positional Description
Argument resolution Type INTEGER Mode Positional Description
Description

Returns the A5 cells covering an arbitrary geometry at the given resolution. Points map to their containing cell, lines are traced, and polygons are filled by cell-center containment by default (holes excluded); MULTI* and GEOMETRYCOLLECTION inputs are unioned. The optional third overlapping argument additionally includes cells that merely touch the polygon boundary, for genuinely gap-free coverage. The result comes back compacted, which is the right shape for storage and set operations — but cell boundaries at different resolutions don't nest geometrically, so call a5_uncompact to a single resolution before drawing the covering as geometry (skip that and a mixed-resolution result will show phantom gaps that aren't really there).

1 Example 1 
SELECT a5_geometry_to_cells('MULTIPOINT((0 0), (10 10))'::GEOMETRY, 8);

Output

a5_geometry_to_cells(CAST('MULTIPOINT((0 0), (10 10))' AS "GEOMETRY"), 8)
[5694194798391459840, 6240643281303109632]
Related functions