Two examples of web maps that use postgreSQL-PostGIS-Geoserver as the backend.

While the open source community has developed many powerful server-side tools for
distributing geographic data and maps on the web, many client interfaces are often
lacking, which can sour a user’s experience and interfere with the presentation of
the data.  In some cases the client interfaces offer too little functionality to
allow exploration of the data; in other cases there is so much functionality that the
user is overwhelmed.   Other concerns relate to the adoption of certain technologies.
 Will a user take the time to find and install the SVG plug-in?  Is JavaScript
enabled?   Does the user have Java on their machine?

Adobe Flash is one of the technologies a designer can choose to deliver geographic
data and maps.  Through the Flash scripting language, a high level of interactivity
can be combined with attractive graphics to provide a rich user experience.  Flash
can communicate with open source web map services via XML and display the requested
geographic data in both raster (WMS) and vector (WFS) formats.  The Flash “player”
plug-in is on 97% of internet-enabled computers worldwide.

We have used Flash for many web mapping tools; here we present two examples that use
PostGIS and Geoserver, both of which are open source, as the backend.  The
Pennsylvania Cancer Atlas displays choropleth maps, cumulative frequency plots, and
tables showing the rates of various cancers for the counties of Pennsylvania.  The
maps, plots, and tables are all dynamically linked.  The Soil Extent Mapping tool
shows the acreages and geographic extent of over 22,000 soil series in the United
States, and allows searches by series name and soil taxonomy.