Spatial Data Management at the Environment Agency – A Technical Perspective

Spatial Data Management at the Environment Agency

A Technical Perspective

Jo Cook | Astun Technology | @archaeogeek

Who are Astun Technology?

We're a geospatial consultancy, established in 2006, supplying enterprise geospatial solutions to a wide-range of customers, based on the open source geospatial stack.

Our customers include, but are not limited to, local and central government, emergency services, and transport management.

Project Background

Astun's Involvement

Astun won the tender to provide this service, began work in 2014 and completed the project in 2015(*)

(*) We are now providing ongoing support to the Environment Agency, as well as working on additional phases of work and enhancements to the service

Requirements

The EA had a set of functional and non-functional requirements that this system needed to meet from the start (*):

• INSPIRE/Gemini 2.2 compliance
• Spatial and non-spatial records
• Schematron-based metadata validation
• Browser-based and externally hosted
• Capable of handling 14,000 records and 150 concurrent users
• Strict security

(*) These requirements have evolved and been added to throughout the project

The Infrastructure and Software

The basic platform comprises the Geonetwork metadata catalogue, backed by the PostgreSQL database server, with PostGIS and Auditing extensions installed

These are installed on a set of Amazon Web Servers (AWS and RDS), with backups in different availability zones, IP restricted access, separate development servers and so on.

Why Geonetwork?

It's the leading open source metadata catalogue tool, with full support for UK Gemini/INSPIRE, and a graphical user interface for viewing, creating and editing data.

It also contains a set of back-end services for working with the metadata programatically

Why PostgreSQL?

We use PostgreSQL to store the metadata and catalogue configuration, and PostGIS to store the spatial indices for geographic searches

The use of the Audit extension means we can track changes made to both metadata records and the catalogue configuration (users, groups, metadata categories etc) and roll back individual changes as necessary, recovering accidentally deleted or corrupted records, and tracking which user did what

We can also take daily/weekly snapshots of the database for disaster recovery and deploying test/development servers, and use the PgAdmin3 graphical user interface to query the data

System Enhancements

“Can we record additional metadata elements that are not part of INSPIRE/Gemini?”

“Yes, but we'll need to build you a new metadata profile that extends UK Gemini”

This became known as EAMP, and now allows custom validation rules for metadata, on top of what's required for UK Gemini

“Can we strip these elements, along with any personal details from metadata records before we publish them to data.gov.uk?”

“Yes, using XSL transformation scripts”

This now prevents internal users even printing copies of metadata records with personal details in

“Can we only publish some metadata to data.gov.uk but allow internal staff to view all completed records?”

“Yes, using a second public-facing server”

Records to be pubished to data.gov.uk are now pushed to a public server and anonymised, then served via CSW (catalog services for the web)

“Can we make changes to selected records in bulk without needing to download them all?”

“Yes, using python scripts and Geonetwork XML services”

We now have scripts to do a number of bulk changes to the data, such as publication date changes, internal contact detail changes and so on

Additional application to allow pushing from private to public server

Project Expansion

June 2015 statement by Liz Truss, Secretary of State for Environment, Food and Rural Affairs

In other words, by June 2016

With very short notice, the EA solution was expanded to take on board 7 other Defra agencies, and the work to meet the June deadline is on target

Phew

So we spun up a second private Geonetwork server for the Defra bodies

Ending up with an architecture something like this

The Good, the Bad and the Ugly

The Good

The client seemed to think it was a success!

EA have already surpassed their OpenData release commitment

We've contributed enhancements to both Geonetwork Code and Documentation

We've released all of our customised code and helper scripts on GitHub

We've even contributed to the improvement of data.gov.uk!

The Bad

We had to stick with an old version of Geonetwork as the EA were on Internet Explorer 9

Versus Geonetwork 3

Certification

Government compliance certification meant we had to jump through fairly arcane hoops and add complexity to the system to get it certified

This was costly to implement, not always appropriate for the solution we have provided, and exacerbated by working with out-sourced ICT providers

The Ugly Annoying

Extending the system we built for the EA to include the other Defra bodies, at short notice, pushed the boundaries of how Geonetwork, and our additional code, is implemented

Upgrading the system to a later release of Geonetwork would mean we would need to go through compliance testing again

Some of the coding decisions in Geonetwork core are ...interesting

This all leaves us with some technical debt and "challenging" work-arounds

People care about what gets published to data.gov.uk and will call you out for any mistakes/discrepancies

The Future

• Move to Geonetwork 3?
• Properly extend the architecture so that all Defra bodies have the same system as EA?
• Implement different metadata profiles such as Medin (for the Marine Management Organisation)?
• Integrate with external authentication mechanisms for user and password management?

Summing Up

The Environment Agency took the strategic decision, and some would say risk, to go with an open source solution for their metadata management

EA and Astun collectively have made this project a success, and helped some of the other Defra bodies meet their open data publishing commitments

The flexibility of open source has allowed us to cope with changing requirements throughout the project, albeit with some technical debt

Finish

Thanks for listening!