OGC Web Services for accessing Geographic Data

The Open Geospatial Consortium has defined several Open Web Services for accessing (usually geographic) data. There are two basic service sets - the Web Feature Services (WFS) and the Web Map Services (WMS). The WFS is concerned with direct access to your data - reading, writing, and updating your features. The WMS is concerned with transforming your data into a map (image).

![](http://udig.refractions.net/confluence/images/icons/emoticons/information.gif) **What is a Feature?** A feature is an Object that is an abstraction of a real world phenomenon. This object has a set of properties associated with each having a name, a type, and a value. An example of a feature might be Road with a Name, Location (line geometry), Width, Speed Limit, and Jurisdiction. Typically these features are stored in a [spatial database](http://udig.refractions.net/confluence/pages/viewpage.action?pageId=5223), shapefile, or other format.
![](http://udig.refractions.net/confluence/images/icons/emoticons/check.gif) **OGC Open Web Services** The OGC Web Services provide access to the features - either directly or as images (maps) - in a standardized way independent of the company who created the server or the actual format the data is stored in.

What to use a the WFS services for

A WFS allows uniform direct access to the features stored on a server. Use a WFS when they want to perform actions such as:

  • query a dataset and retrieve the features

  • find the feature definition (feature’s property names and types)

  • add features to dataset

  • delete feature from a dataset

  • update feature in a dataset

  • lock features to prevent modification

A WMS allows for uniform rendering access to features stored on a server. Use a WMS when you want to perform actions such as:

  • Producing Maps

  • Very simple Querying of data