Geo-spatial filtering alongside vector search
Geo-spatial filtering restricts results by location (e.g. within a radius, inside a polygon) stored as metadata (lat/lon or geo types). Combined with nearest-neighbor vector search, you get “similar items near this place”—e.g. similar products in a region, or nearby points of interest with semantic match. Implementation options include pre-filtering or post-filtering on geo fields, or dedicated geo indexes alongside the vector index, with the usual trade-offs for ANN.
Summary
- Geo-spatial filtering restricts results by location (within radius, inside polygon) stored as metadata (lat/lon or geo types). Combined with nearest-neighbor search: “similar items near this place.”
- Implementation: pre-filter or post-filter on geo fields, or dedicated geo indexes alongside the vector index; same trade-offs for ANN. Geo index types, distance units, and how metadata and range queries apply to coordinates vary by VDB. Pipeline: parse geo predicate, use geo index or scan, intersect with vector ANN. Practical tip: index geo fields when you often filter by location.
Geo indexes and filtering
Location is stored as metadata (lat/lon or geo types such as point, polygon). Filtering by geo can be pre-filter (e.g. geo index returns candidate IDs, then vector search) or post-filter (vector search first, then filter by location). Pre-filter reduces work when the geo constraint is selective; post-filter is simpler but may require over-fetching.
Geo index types and distance units vary by VDB: some support within-radius (e.g. 10 km), inside-polygon, or bounding box. Pipeline: parse geo predicate → use geo index or scan to get candidate set → intersect with vector ANN or run vector search then filter. Trade-off: same as other metadata—pre-filter is more efficient when selective. Practical tip: index geo fields when you often filter by location; check docs for distance units (miles vs. km) and coordinate systems.
Combining with vector search
Combined query: similar items near this place. The vector index returns by similarity; the geo filter restricts to a region. Implementation may use a dedicated geo index alongside the vector index, or metadata/range queries on coordinates. See metadata filtering and range queries for how filters combine with ANN.
Frequently Asked Questions
What is geo-spatial filtering with vector search?
Restrict results by location (e.g. within radius, inside polygon) stored as metadata (lat/lon or geo types), combined with nearest-neighbor vector search. Use case: similar products in a region, or nearby points of interest with semantic match.
Pre-filter or post-filter for geo?
Same trade-offs as other metadata: pre-filter (or dedicated geo index) can reduce work when selective; post-filter is simpler. See why pre-filtering is hard for ANN.
Do I need a separate geo index?
Some VDBs support geo as metadata with range or special geo predicates; others offer dedicated geo indexes alongside the vector index. Check docs for distance units and coordinate support.
How does this relate to metadata filtering?
Geo is a form of metadata filtering; coordinates are stored with each point. Filter expression might be within 10km of (lat, lon) or inside polygon. Implementation may use geo index or bitsets for combination with vector search.