The explain() method in MongoDB provides detailed information about how a query is executed, allowing you to analyze its performance characteristics. By using explain(), you can understand the query execution plan, which helps in optimizing queries for better performance.
Geospatial indexing in MongoDB allows you to perform queries on geometric data types like points, lines, and polygons. These indexes are particularly useful for location-based services such as mapping, routing, and geofencing. MongoDB supports two main types of geospatial indexes: 2d indexes and 2dsphere indexes.