postgis-spatial

Use ST_Intersects or ST_Contains with geometry columns in PostGIS to filter candidate places against a defined region. Store geometries with SRID 4326, create a GiST index on the geometry column, and query using spatial operators to return matching locations.

ST_Intersects checks if geometries overlap, ST_Contains verifies if one geometry fully contains another, and ST_DWithin filters by distance. Combine these with GiST indexes on geometry columns for efficient spatial queries across large candidate datasets.

Yes. ST_DWithin filters places within a specified distance of a point or region, leveraging GiST indexes for performance. Use it in WHERE clauses to generate candidate sets based on geographic proximity without computing all pairwise distances.

Store different geometry types (points, polygons, lines) in the same column with consistent SRID handling, typically SRID 4326 for geographic data. Use spatial operators like ST_Intersects and ST_Contains to work across mixed geometry types in a single query.

GiST indexes accelerate spatial queries by indexing geometry bounds, enabling fast filtering of large candidate sets. Without indexes, ST_Intersects, ST_Contains, and ST_DWithin queries perform full table scans, degrading performance on datasets with many geometries.

A plpgsql function can encapsulate region-based filtering logic, applying ST_Intersects for included regions and ST_Disjoint for excluded ones. This simplifies repeated queries and centralizes spatial logic for candidate filtering workflows.