OGC and WFS Tuesday, April 27, 2004

What is OGC?
The Open GIS Consortium, Inc. (OGC) is a member-driven, non-profit international trade association that is leading the development of geoprocessing interoperability computing standards. OGC works with government, private industry, and academia to create open and extensible software application programming interfaces for geographic information systems (GIS) and other mainstream technologies. Adopted specifications are available for the public's use at no cost. For more information, visit the OGC web site at http://www.opengis.org/.

What is WFS?
The OGC Web Feature Service (WFS) allows a client to retrieve geospatial data encoded in Geography Markup Language (GML) from multiple Web Feature Services. WFS allows for clients and servers of different vendors to share data without having to convert between proprietary vendor formats. For specifications on WFS, see http://www.opengis.org/docs/02-058.pdf.

Atlas and WFS
Currently, Atlas has two WFS servers in operation in a test mode. First, the Louisiana WFS site at http://atlas0.lsu.edu/la/request.asp has the Atlas indices for Louisiana and a subset of the features from the Louisiana GIS CD version. The USA WFS site at http://atlas0.lsu.edu/usa/request.asp has the USSampledata warehouse from Intergraph updated with Census 2000 statistics. For more information about these WFS servers and the data that they are serving, click here.

Please note: these WFS sites are still in test mode. Expect changes in these sites as testing progresses.

How to use WFS with your GIS
The GIS and mapping vendors have not yet enabled WFS in the initial deliveries of their software. However, many vendors are providing add-ons, extensions, extended applications, etc. to give their applications the ability to use WFS.

For Intergraph Geomedia (version 5.1)
  Download the WFS dataserver as zip file by clicking on WFS_Dataserver_05.01.06.00.zip. Unzip the contents of this zip file into a temporary directory and run the setup.exe file.
  Visit the ESRI site at http://www.esri.com for more information. Another source for ArcGIS WFS support is the Geoleaders web site at http://www.geoleaders.com/.
For Mapinfo
  Visit the Geoleaders site at http://www.geoleaders.com/
For other GIS, mapping, and CAD applications
  See the web sites of their vendors for more information.

Important Note:
Since WFS is operating at network speeds, it is slower than having a dataset stored locally on a hard drive. A user who uses WFS connections for heavily used features would be at the mercy of the network. Instead, users should think of WFS as a way to "try it before buying it" or, in the case of Atlas, "try it before downloading it" (since all Atlas data is free!). Users should use the WFS capability for viewing features and then downloading all or some of the desired features. Since some GIS applications, such as Intergraph's Geomedia, see the WFS features no differently from features from other data sources, the downloading step is nothing more than saving the WFS features to a local file. No need to download a Winzip file from Atlas!