r-tree

http://www.sqlite.org/rtree.html says that the r*tree is "included as part of the amalgamation but is disabled by default" and to enable it "simply compile with the SQLITE_ENABLE_RTREE C-preprocessor macro defined" Well I want to use R-trees in my android app, but clearly SQLite is all pre-installed etc. Is there a way to enable it on a user's phone/device? Alternatively, is it possible to use the NDK and the freely available source code for SQLite? You can absolutely compile your own version of SQLite. We do this in order to enable the encryption/codec modules from wxSQLite. Take a look at

I looked at the definition of KD-tree and R-tree. It seems to me that they are almost the same. What's the difference between a KD-tree and an R-tree? R-trees and k d-trees are based on similar ideas (space partitioning based on axis-aligned regions), but the key differences are: Nodes in k d-trees represent separating planes, whereas nodes in R-trees represent bounding boxes. k d-trees partition the whole of space into regions whereas R-trees only partition the subset of space containing the points of interest. k d-trees represent a disjoint partition (points belong to only one region)

Does anyone know a good and simple to use in production code R-tree implementation? (actually, any implementations - R*, R+ or PR-tree would be great) It doesn't matter if it is a template or library implementation, but some implementations that Google found look very disappointing... Check R-Trees code on http://www.superliminal.com/sources/sources.htm also check http://www.virtualroadside.com/blog/index.php/2008/10/04/r-tree-implementation-for-cpp/ You may also check out the rtree variants provided by the Boost.Geometry library: http://www.boost.org/doc/libs/release/libs/geometry/doc/html

I need a commercial-friendly (Apache Licence, LGPL, Mozilla Public License etc) R-tree implementation in Java, in order to substitute the geonames Web Service for timezones, as suggested in the question " Determine timezone from latitude/longitude without using web services like Geonames.org ". I have found some around , but I was wondering if someone has evaluated or used them in practice. WindRider https://github.com/rweeks/util/blob/master/src/com/newbrightidea/util/RTree.java - LGPL implementation of R-Tree by Russ Weeks. It looks very simple and clear and not dependent on external

MySQL支持的索引类型 MySQL支持多种索引类型，每一个存储引擎对其有着不同程度的支持。 MySQL支持以下四种索引，具体支持情况见下表： 索引 MyISAM InnoDB Memory B-Tree 支持 支持 支持 HASH 不支持 不支持 支持 R-Tree 支持 不支持 不支持 Full-Text 支持 不支持 不支持 B-Tree 算是平时用到最多的一种索引类型，大部分引擎都支持。 Hash 目前只有Memory支持，对于等值查询有着较高的效率，不支持范围查询。 R-tree 空间索引，在MyISAM中实现，用于地理位置的查询。 Full-Text 全文索引，紧在MyISAM中支持，MySQL5.6后InnoDB也开始支持。 支持的索引规则 1、最左前缀规则，使用a、b、c联合索引的时候，需要按从左到右的顺序进行SQL的查询，可以包含一部分字段，比如只根据a进行检索也可以使用索引，但是不可以颠倒顺序进行查询。 2、只查询索引中的字段，比如： //简单的登陆SQL，假设username为唯一索引，id为主键 SELECT * FROM user WHERE username = 'fuckphp' AND password = 'fuckphp'; //如上SQL的效率会比下面的效率低 SELECT id FROM user WHERE username =