GPS probe map matching algorithm based on spatial data model

To improve the performance of the traditional map matching algorithms in freeway traffic state monitoring systems using the low logging frequency GPS （global positioning system） probe data, a map matching algorithm based on the Oracle spatial data model is proposed. The algorithm uses the Oracle road network data model to analyze the spatial relationships between massive GPS positioning points and freeway networks, builds an N-shortest path algorithm to find reasonable candidate routes between GPS positioning points efficiently, and uses the fuzzy logic inference system to determine the final matched traveling route. According to the implementation with field data from Los Angeles, the computation speed of the algorithm is about 135 GPS positioning points per second and the accuracy is 98.9%. The results demonstrate the effectiveness and accuracy of the proposed algorithm for mapping massive GPS positioning data onto freeway networks with complex geometric characteristics.

三种关系型空间数据库比较

空间数据库在GIS的组成中起着关键作用,可以说它支持GIS的发展。如何有效地存储、查询、检索空间数据成为地理信息系统的关键。空间数据类型、索引、函数,这三个方面将空间数据与数据库关联在了一起。空间数据类型用于指定图形是点、线、还是面;空间索引用于有效处理空间数据;该函数内置于SQL语言中,用于查询属性信息和空间数据之间的联系。这三者的有机组合提供了灵活的结构用于优化性能和分析。而不同的空间数据库,因索引和函数的不同,也有着各自的优势和不足。了解一些广泛使用的关系型空间数据库,例如Oracle spatial、PostGIS、MySqL GIS。对它们进行简单的对比,可以让用户在空间数据的管理方面,根据个人的需要,进行最优的选择。