Managing environmental knowledge and the necessary IT tools - Environmental Deterioration and Contamination: Problems and their Management - page 444

Figure 12.9 Sample xml file.

Figure 12.10 Interactive maps with online access to read and write (2013).

- HTML: HTML code is used to display popup balloon. In the HTML codes, you

must use HTML tags “&lt;'' instead of “ < '' and “&gt;'' instead of “ > '' so as not
to confuse the XML code;

- label: info displayed in tool tip window when the mouse cursor is over the point.

This XML technology is effective only for a few dozens of points. Google Maps
are accessed using Google Maps API 3, the free JavaScript library to display.
We have set up our own spatial database using PostGIS/PostgreSQL spatial
database server (Obe & Hsu, 2011) to publish large spatial data sets. A spatial database
stores GIS data (map objects and attributes) in a relational database, and the SQL
(Sequential Query Language) is used to access and update spatial data. To publish
the spatial data to the clients, a MapServer component is needed. MapServer is used
to serve standardized WEB map service (WFS and WMS) for the clients (Michell,
2005). Our digital map uses the OpenStreetMap (OSM) as a background layer from
the osm.org server (Figure 12.10). The clients connect to the ENFO WMS/WFS sever
and the OSM server using OpenLayers JavaScript library.
The mapping applications have only Hungarian user interface at this moment.