FDO Provider for WMS
The Feature Data Objects (FDO) API provides access to data in a data store. A provider is a specific implementation of the FDO API that provides access to data in a particular data store. The FDO Provider for WMS provides FDO with access to a WMS-based data store.
An Open Geospatial Consortium (OGC) Web Map Service (WMS) produces maps of spatially referenced data dynamically from geographic information. This international standard defines a "map" to be a portrayal of geographic information as a digital image file suitable for display on a computer screen. A map is not the data itself. Maps by WMS are generally rendered in a pictorial format, such as PNG, GIF or JPEG.
The FDO Provider for WMS has the following characteristics:
- The FDO Provider for WMS serves up map information originating from an OGC Basic Web Map Service that provides pictorially formatted images, such as PNG, GIF, or JPEG.
- WMS map data is exposed through an FDO feature schema whose classes contain an FDO Raster property definition. The FDO schema exposed from the FDO Provider for WMS conforms to a pre-defined FDO schema that is specific to WMS and that acts as the basis for all FDO interaction with WMS data, regardless of the originating source of the WMS images.
- WMS data manipulation operations are limited to querying features based on spatial and non-spatial constraints. Schema manipulation operations are not supported.
The FDO Provider for WMS can run in a multi-platform environment, including Windows and Linux.
Connecting to the WMS Provider
This information supplements the Establishing a Connection chapter in the FDO Developers Guide.
You can connect to FDO Provider for WMS by specifying the URL corresponding to the WMS Server that you want to use.
Specifying the WMS Server URL is the minimum required connection properties for the initial call to Open(). Access to the server may be password-protected in which case a Username and password must also be supplied.