An Open Source GIS Architecture for

Connected and Linked Data

Jerry HayesFrank Hardisty (Advisor)

Problem: Relational database abstraction impedes performance and scalability.

Connected Data in GIS Today

Many use cases in GIS

Creates logical model to represent topology.

Storage of logical model is not optimal.

Problem: Vast potential of the Semantic Web is unrealized in GIS!

Linked Data in GIS Today

Links described by semantic relationships.

Semantics enable data discovery.

Early stages of adoption in GIS.

Having trouble “visualizing” the network ? … so do machines!

How GIS Stores Connected Data Uses relational database tables

Abstraction introduces unnecessary overhead.

Bad for large datasets!

Much easier to visualize network … machines are happier too!

Graph Databases for Connected Data Stores connected data in its native format.

Removes unnecessary overhead.

Good for large datasets!

Performance comparisons are difficult. … how “connected is the connected data?

Preprocessing data helps mitigate issues. … ESRI’s preprocessed logical network model.

In general … i) RDBMS are optimized for aggregation queries ii) Graph databases are optimized for traversing.

Database Performance Comparisons

Two basic properties define graph databases.

Graph Database Characteristics

Native Graph StorageNati

ve G

raph

Pro

cess

ing

Connects data to data on the Web

Uses Resource Descriptive Framework (RDF).

Creating quality linked data is challenging!

Linked Data … the Next Frontier

Only useful in sufficient quality and quantity.

Many RDF datasets are now available

Data quality, availability and stability concerns.

Tools are available for accessing RDF models.

LinkedGeoData for GIS applications.

Accessing Linked Data

Server side is stateless.

PostGIS used for .. • Storing physical model.• Data visualization.

Neo4j used for …• Storing logical model• Graph traversals

Open Source System Architecture

Implemented in the IBM Cloud

Provides RESTful API.

Enables spatial analytics

Enables “data” discovery.

Integrates physical and logical model processing.

Implemented in the IBM Cloud

Servlet Architecture