ST_SNAP_TO_GRID()

All functions > GEOSPATIAL > ST_SNAP_TO_GRID()

Snaps all vertices of a geometry to a uniform grid with the given cell size.

Signatures

Snap to grid

Returns: Geometry with snapped vertices; sub kind is preserved but may collapse to empty

ST_SNAP_TO_GRID(geo: T, size: DOUBLE) → GEOM_MULTIANY

With:

• T : Custom types: GEOM_POINT | GEOM_LINESTRING | GEOM_POLYGON | GEOM_MULTIPOINT | GEOM_MULTILINESTRING | GEOM_MULTIPOLYGON | GEOM_MULTIANY

Signature notes:

• Rounds each vertex coordinate to the nearest multiple of size
• Snapping follows spatial grid rules; behavior at exact half-step boundaries can differ from naive scalar rounding of coordinates alone
• May collapse small geometries to empty if the grid is coarser than the shape
• May produce invalid geometries (self-intersections) after snapping; validate with ST_ISVALID
• GEOMETRY only; for geographic use, reproject first: ST_TRANSFORM to a metric CRS, snap, then ST_TOGEOGRAPHY
• Not supported on Trino or DataFusion
• Returns NULL if any input is NULL

Examples

SELECT
    f1 := ST_ASTEXT(ST_SNAP_TO_GRID(ST_GEOMPOINT(1.23456, 7.89012), 0.01)) -- Snap a point to a 0.01 unit grid
;