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| |
| # ST_Within |
| |
| Introduction: Tests whether geography `A` is fully within geography `B` using S2 spherical boolean operations. Returns true when every point of `A`'s interior lies in `B`'s interior. By OGC convention, `ST_Within(A, B)` is equivalent to `ST_Contains(B, A)`, and shares the same boundary semantics. |
| |
| Polygon ring roles follow the simple-features structure: the first ring is a shell and subsequent rings are holes, regardless of input winding. Sedona preserves the submitted coordinate order for structural output such as `ST_AsText`, while normalizing only the S2-facing traversal used by spherical operations. |
| |
| Each Geography polygon shell is normalized to an area of at most one hemisphere. A shell intended to represent more than half the sphere is therefore interpreted as its complement; reversing the ring's coordinate sequence does not select the larger region. |
| |
| Boundary semantics on the sphere are inherited from S2's boolean operations and depend on the normalized S2 edge orientation: along an edge that is "owned" by `B`'s boundary the test returns true, and along the opposite edge it returns false. Do not rely on a specific result for points that lie exactly on `B`'s boundary; for predictable behavior, use a strict interior point or expand `B` slightly with `ST_Buffer` before testing. |
| |
|  |
|  |
| |
| Format: |
| |
| `ST_Within (A: Geography, B: Geography)` |
| |
| Return type: `Boolean` |
| |
| Since: `v1.9.1` |
| |
| SQL Example — interior point: |
| |
| ```sql |
| SELECT ST_Within( |
| ST_GeogFromWKT('POINT (0.5 0.5)', 4326), |
| ST_GeogFromWKT('POLYGON ((0 0, 1 0, 1 1, 0 1, 0 0))', 4326) |
| ); |
| ``` |
| |
| Output: |
| |
| ``` |
| true |
| ``` |
