To summarize: a WMS 1.3.0 has a server-dependant means of specifying both the sources of data (the Layers) and the means of portraying that data (the Styles). These quantities are completely under the control of the server and no means is specified for the clients to designate additional data or custom symbolization. Clients may only choose from a list of options supported and advertised by the server.
Definition of Terms
- Layer basic unit of geographic information that may be requested as a map from a server
- Style (not formally defined) a basic unit of portrayal information
- Portrayal presentation of information to humans
Basic Portrayal Service
The basic portrayal service interface as defined by ISO 19117 is very simple. Its one operation called "portrayFeature" takes two arguments: a list of feature instances to portray and a list of portrayal catalogues, which define how the feature is to be portrayed. This operation returns nothing and specifies nothing further.
ISO 19117 places no constraints on the allowed presentation of information. It specifically states that portrayal may include such things as audible cues or output from a tactile device (for the visually impaired). WMS 1.3.0 is geared toward producing one or more 2D raster images in a number of supported formats.