ST_Covers

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Given two shapes A and B, predicate function ST_Covers(A, B) returns true if no point in B lies outside of shape A. Otherwise, it returns false.

In other words, shape A must completely cover every point in B.

This behavior is similar to ST_Contains, except that the criteria for ST_Contains are more exacting, and therefore some pairs of shapes will be accepted by this function that would be rejected by ST_Contains.

ST_Covers works on the following data types:

• GEOMETRY
• GEOGRAPHY

Examples

True

In this example, ST_Covers returns true because:

• No Point in the smaller Polygon B lies outside of the larger Polygon A.

SELECT ST_Covers(st_geomfromtext('SRID=4326;POLYGON((-87.906471 43.038902, -95.992775 36.153980, -75.704722 36.076944, -87.906471 43.038902))'), st_geomfromtext('SRID=4326;POLYGON((-87.623177 41.881832, -90.199402 38.627003, -82.446732 38.413651, -87.623177 41.881832))'));

   st_covers
---------------
     true

(1 row)

False

In this example, ST_Covers returns false because:

• Many Points in the smaller Polygon B lie outside of the larger Polygon A.

SELECT ST_Covers(st_geomfromtext('SRID=4326;POLYGON((-87.906471 43.038902, -95.992775 36.153980, -75.704722 36.076944, -87.906471 43.038902))'), st_geomfromtext('SRID=4326;POLYGON((-84.191605 39.758949, -75.165222 39.952583, -78.878738 42.880230, -84.191605 39.758949))'));

   st_covers
---------------
     false
(1 row)

See also

• Working with Spatial Data
• Spatial and GIS Glossary of Terms
• Spatial indexes
• Spatial functions
• ST_CoveredBy
• ST_Contains
• ST_Within
• ST_Intersects
• ST_CoveredBy
• ST_Disjoint
• ST_Equals
• ST_Overlaps
• ST_Touches
• ST_ConvexHull
• ST_Union
• Migrate from Shapefiles
• Migrate from GeoJSON
• Migrate from GeoPackage
• Migrate from OpenStreetMap
• Introducing Distributed Spatial Data in Free, Open Source CockroachDB (blog post)