This presentation will introduce a high level idea of creation of a web service that returns the map content generated "on the fly". It will show how to implement any custom logic, analysis, data calculation, data interoperability and present the output on the map within the request's time span. In the heart of the service you will see Mapserver-Mapscript library. Nowadays building a web-mapping system to show maps from static data like vector and raster files seems to be an obvious task. For more complex solutions we need to make the mapping system “more intelligent”. The content of the map should be calculated, processed, transformed, fetched, created “on the fly” depending on some specific logic. To implement it, we need the proper architecture, technology and solution. Not each way is optimal, fast, smart and easy enough. Sometimes technology exploration is time consuming but the solution could be very simple. This presentation will give you some idea of creating a web service which returns the dynamic map content using Mapserver-Mapscript library and Geoserver. Authors and Affiliations – Bartlomiej Burkot Requirements for the Attendees – To understand the web mapping system structure: Understand what is WMS, basics of programming, networking. Track – Software Topic – Software/Project development Level – 2 - Basic. General basic knowledge is required.