Full-text search and geospatial queries

Why this matters

MongoDB ships two specialist index types that open up query patterns impossible with standard B-trees: text indexes for natural-language keyword search with stemming and stop-word removal, and 2dsphere indexes for proximity queries like 'find all restaurants within 2km of this GPS coordinate'. These capabilities matter because the alternative — pulling data into Elasticsearch or PostGIS — adds operational complexity, synchronization lag, and consistency risk. For applications where full-text or geo requirements are modest, MongoDB's built-in support is often enough, and understanding the limitations (one text index per collection, no relevance scoring tuning) helps you decide when to stay native vs. reach for a specialist.

Demo

Create a text index for product search and a 2dsphere index for location-based queries.

Try it yourself

1. Insert 10 stores at known GPS coordinates. Query for stores within 500m, 1km, and 5km of a central point. Verify the result counts increase with radius and match what you expect given the coordinates.
2. Create a text index on name and description. Search for a word that appears in only one field. Then search for a phrase in double quotes. Note how phrase search differs from keyword search in results.
3. Attempt to create a second text index on the same collection. Observe the error MongoDB returns. Look up the one-text-index-per-collection limitation and explain why it exists.

Prompt your AI

Use these three in order. Each builds on the one before.

1. Basics & terminology

Explain MongoDB's text search. What is a text index, what does it store, and what does the $text query operator do?

2. Why it works (the mechanism)

How does MongoDB's 2dsphere index store coordinates internally? What is the difference between $near and $geoWithin, and when would you use each?

3. Advanced — application & what's next

I need relevance-ranked text search with field boosting (title matches should outrank description matches). MongoDB text search doesn't support field boosting. What are my options?

References

• Text Search — MongoDB docs
• 2dsphere Indexes — MongoDB docs