Global Positioning System Reference
In-Depth Information
The default coordinate reference system for an earth-like sphere
(GeoJSON object) in MongoDB is the WGS84 datum.
MongoDB stores data in a binary JSON-like format called BSON.
MongoDB supports the following GeoJSON objects: Point, LineString,
Polygon, MultiPoint, MultiLineString, MultiPolygon, Feature,
FeatureCollection, and GeometryCollection.
The following topics summarise the spatial characteristics of
MongoDB:
• SRID: the coordinate system expected by MongoDB is WGS84.
MongoDB does not provide re-projection operations;
• Functions: MongoDB provides support for topological functions
(within and intersects). There is no support for analysis functions
(buffer, convexHull) or set functions (intersection, union, difference,
symDifference).
Neo4j
The Neo4j—Network-oriented database for Java—is an open source NoSQL
graph database system developed using the Java Programming Language.
Neo4j was offi cially launched in 2010 by Neo Technology.
Neo4j is called embeddable because it can be added to a Java application
like any library. The data model adopted to express the stored information
is based on the graph theory (Diestel 2005), comprised of nodes, properties
and relationships eventually connecting some of the nodes.
The graph database is suitable for processing linked data. This
type of database is usually found in applications related to areas such
as telecommunications, logistics, social networks, bioinformatics, and
detection of fraud (Hunger and Rathle 2012).
Main Features
Neo4j has a native storage manager completely optimised for storing graph
structures to provide maximum performance and scalability. The system can
handle graphs containing several billion nodes, relationships and properties
stored on a single machine (Hoff 2009).
Neo4j provides a graph-oriented data representation rather than static
tables with rows and columns. Therefore, it is possible to work with a
network composed of fl exible graph nodes, relationships, and properties.
The edges of a graph represent relations and can be directed or not. The
vertices are labeled and generally have properties represented by one or
more key/value pairs, and can hold several edges simultaneously, each one
representing a specifi c relationship with other vertices (Baas 2012).
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