According to R-Trees: Theory and Applications by Yannis Manolopoulos, Alexandros Nanopoulos, Apostolos N. Papadopoulos and Yannis Theodoridis, there are a number of algorithms for efficiently determining the nearest neighbor(s) using an R-Tree (an internet search on the two terms will pull up several). There are two things to keep in mind about this: 1. You would need to access SQLite's R-Tree "shadow" tables (xx_node, xx_parent, xx_rowid) directly in to perform the traversals required by all of the algorithms -- I don't know if this is officially supported by SQLite's developers, or if these tables are guaranteed not to change; 2. If your dimension is > 1, the R-Tree alone can't give you a reliable answer about who is closer, you would also need a method to calculate the minimum distance between two indexed objects. Peter
On Thursday, August 21, 2014 2:32 PM, skywind mailing lists <mailingli...@skywind.eu> wrote: > > >Hello, > >does anybody have any experience with implementing a nearest neighbor search >using SQLite's RTree functionality? Is a nearest neighbor search possible? > >Regards, >Hartwig > > >_______________________________________________ >sqlite-users mailing list >sqlite-users@sqlite.org >http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users > > > _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users