1. Open Geospatial Consortium (OGC) and Web Services (WMS, WFS)

Introduction

Every day, more people use the World Wide Web to get geospatial information.

According to McKee (2001) what is happening in the world of the "Spatial Web" is the following:

• As the Spatial Web grows, there are more online spatial resources available. And while these resources are getting simpler to use, there is increasing potential for extended capability and complexity in Web mapping applications.
• As Web sites become richer in processing resources, users will need to own less software and their sessions on the Web will become more interactive.

Until now, data sharing between institutions that use software from different vendors was difficult, because of the various formats.

That is why Open Geospatial Consortium (OGC) began in 1994 to enlist vendors of GIS software (and other organisations) in a technical committee process to reach consensus on open interfaces that would enable their systems to communicate across networks. OGC's highly successful 1999 Web Mapping Testbed prompted the consortium to make testbeds for its main method: the development of specifications. These specifications are software interface specifications that provide a common software syntax and semantics for system-to-system requests in distributed geospatial computing environments. They provide the foundation for making Web mapping as open as the Web itself. (McKee 2001)

Today, luckily, almost all of the geoprocessing software vendors ("old" and new ones) focus on Web mapping where interoperability is of highest priority. Therefore, the chore of downloading, converting and merging spatial data is becoming increasingly unnecessary. (McKee 2001)

This lesson will list a few specifications that OGC developed for Web Mapping issues and go into further details of the specifications "Web Map Service" and "Web Feature Service". Exercises should help to understand how these services work.