Time for a quick look ‘under the hood’ at how we’re building the new Land Registry online index map which I blogged about recently and which you can read about on the Government Digital Service pages.

Biggest Map Search

We’re using a variety of free, open source software. Here’s the detail:

Spatial data

The spatial data, which is held in an Oracle-based Enterprise Data Warehouse, is accessed by an open source server called GeoServer, running on a standalone Apache Tomcat server. GeoServer allows access to both the Land Registry map polygons and their attribute information (title number and tenure information), but also the address information.

Map element

The map element itself uses OpenLayers, which is a pure JavaScript library for displaying map data in most modern web browsers. This in turn uses Proj4js, a JavaScript library to transform coordinates from one coordinate system to another, allowing geographic data stored in different projections to be combined in browser-based web mapping applications.

At the front end

The application itself also uses JQuery, a multi-browser JavaScript library designed to simplify the client-side scripting of HTML. In particular the methods to parse JSONP data requests are used to facilitate ‘cross-origin resource sharing’. For future sprints, it is likely that we’ll use the GeoExt toolkit  for printing. (This, combined with GeoServer and OpenLayers, forms part of the OpenGeo suite of software.)

We’re releasing the beta in September so you’ll be able to take a look at the build then. We are also learning and sharing best practice with the Rural Payment Agency map search, which is another Government Digital Service exemplar project.

Simon Cairns
By Simon Cairns,
Digital Service Delivery Lead at HM Land Registry, Coventry Office