uid: Lucene.Net.Spatial summary: *content

The Spatial Module for Apache Lucene.NET

The spatial module is new to Lucene.NET 4, replacing the old “Lucene.Net.Contrib” module that came before it. The principle interface to the module is a xref:Lucene.Net.Spatial.SpatialStrategy which encapsulates an approach to indexing and searching based on shapes. Different Strategies have different features and performance profiles, which are documented at each Strategy implementation class level.

For some sample code showing how to use the API, see SpatialExample.cs in the tests.

The spatial module uses Spatial4n, a .NET port of the ASL licensed Spatial4j heavily. Spatial4n is a library with these capabilities:

  • Provides shape implementations, namely point, rectangle, and circle. Both geospatial contexts and plain 2D Euclidean/Cartesian contexts are supported. With an additional dependency, it adds polygon and other geometry shape support via integration with NetTopologySuite (often referred to as NTS). This includes dateline wrap support.
  • Shape parsing and serialization, including Well-Known Text (WKT) (via NTS).
  • Distance and other spatial related math calculations.

[!NOTE] Historical Fact: The new spatial module was once known as Lucene Spatial Playground (LSP) as an external project. In ~March 2012, LSP split into this new module as part of Lucene and Spatial4j externally. A large chunk of the LSP implementation originated as SOLR-2155 which uses trie/prefix-tree algorithms with a geohash encoding. That approach is implemented in xref:Lucene.Net.Spatial.Prefix.RecursivePrefixTreeStrategy today.