IDL provides object classes that facilitate communication and file transfer between IDL and several different types of network-based resources.

Generic Network Resources

The IDLnetURL object class provides a mechanism whereby IDL programs can transfer information to and from network servers using the HTTP and FTP protocols. Any data that can be transferred using a web browser or FTP client application can be transferred using the URL object.

Geospatial Network Resources

The Open Geospatial Consortium (OGC) is an open-standards organization devoted to developing standards that govern web-based delivery of geospatial data including geographical information systems (GIS) data combined with location, elevation or other types of structure data. Common OGC specifications include the following three client/server protocols:

  • WMS (Web Map Service): Returns rendered image layers containing information such as roads, topography, or municipal boundaries. The image layers can be combined into a single display.
  • WCS (Web Coverage Service): Returns unrendered data containing sensor data, hyperspectral data, elevation data, or imagery.
  • WFS (Web Feature Service): Returns vectors of GML (Geography Markup Language) data describing elements such as roads, rivers, and property boundaries. This protocol supports creating, deleting, querying and updating vector information on the server.

IDL currently offers support for:

Using these objects, you can access and query servers that support the related OGC protocol (WCS or WMS). See Making OGC WCS Server Requests and Making OGC WMS Server Requests for more information.

The Open Geospatial Consortium web site ( provides full protocol specification details. See the web site to download specific service specifications and XML schema definition documents.