Web GIS originates from a combination of web technology and Geographic Information Systems. Essentially it is a GIS system that uses web technologies to make data accessible to the public regardless of whethter or not they have a background and knowledge about GIS. Hence the main objective of webGIS is informing people through interactive maps. The user interface is very simple and allows a fairly straightforward navigation through the map. WebGIS projects can be built using basic functions, e.g. zoom in and out, or by area, search for place names, and switch on and off the layers. Alternatively, a webGIS can be a bit more complex and allow the users to access the attribute table of the layer by clicking on a feature on the map, editing layers, or filtering the data.
Considering the IT constraints, the internet limitations and the resources available (staff and money) that are shared by the UKOTs in the South Atlantic region, it was necessary to adopt a very simple approach for the development of webGIS services. The simplest architecture of a Web GIS requires one server, with a web application, and one client that is a desktop application or web browser application that allows the user to communicate with the server.
QGIS is the GIS tool used in the Falkland Islands, Ascension and Saint Helena and with the plugin Lizmap provides the simplest platform for creating webGIS services. The steps for publishing online are four:
- Set up the server with GIS, PostgreSQL and web application (Lizmap, Apache, php)
- Create the QGIS project based on data coming from a database (postgresql)
- Use the Lizmap plugin to publish the project online
- Transfer the project and the data via FTP from local to the server with the web applications
Ascension, Saint Helena and the Falkland Islands share one cloud server with the web applications. This is maintained by the data manager in the Falkland Islands. The current system architecture requires that, in order to publish a webGIS service, the data managers from Ascension or Saint Helena send the QGIS projects and the backup of their database (data are all stored in PostgreSQL database except for the raster files which are sent individually) to the data manager in the Falkland Islands who is responsible for uploading them onto the cloud server.