MongoDB Spatial Indexing: Geospatial

Tip: 2dsphere Index

$collection->createIndex(['location' => '2dsphere']);

Required for all geospatial queries.

Gotcha: GeoJSON Format

'location' => [
    'type' => 'Point',
    'coordinates' => [longitude, latitude],
]

Tip: Polygon Search

$collection->find([
    'location' => [
        '$geoWithin' => [
            '$geometry' => [
                'type' => 'Polygon',
                'coordinates' => [[[...]]],
            ],
        ],
    ],
]);

Gotcha: Coordinate Order

Always [longitude, latitude]. Not [latitude, longitude].

Tip: Near Query with Distance

['$geoNear' => [
    'near' => ['type' => 'Point', 'coordinates' => [-73.97, 40.77]],
    'distanceField' => 'distance',
    'maxDistance' => 5000,
]]

Gotcha: Index Required

Without 2dsphere index, geospatial queries do full collection scans.

Tip: Embed or Reference? The 80/20 Rule

If you always access data together, embed it. If you access it independently, reference it. The 16MB document size limit is the hard boundary — stay under 1MB for most documents.

Tip: Index Your Query Patterns, Not All Fields

Creating indexes on every field wastes RAM. Use explain() to find in-memory sorts and collection scans. Index only what your actual queries filter on.

Gotcha: No Transaction Rollback for Index Builds

Building an index on a large collection can take hours. If it fails midway, the partial index is silently discarded. Plan index builds during maintenance windows.

Senior Insight

MongoDB's geospatial queries are excellent for location-based features. I've built near-real-time location tracking using 2dsphere indexes and $nearSphere queries. The key performance insight: $nearSphere requires a 2dsphere index and always returns results sorted by distance. If you need to combine geospatial with other filters (like category or status), create a compound index with the 2dsphere as the first field.

Source: MongoDB Developer Center (https://www.mongodb.com/developer/), MongoDB Engineering Blog (https://www.mongodb.com/blog/channel/engineering-blog), Studio 3T Blog (https://studio3t.com/blog/)