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web, and the Data Aggregation Service, which presents remodeled WFS endpoints as an aggregated WFS.
8.1.3 Display and Navigation System
Clients that provide for visualization at all include software to control the map display, zoom controls, layer ordering and visibility control, legend, etc. This software is
inherently dependent on user interface, both for visualization on output, and user control on input. There are actually several components of this. The map display itself may
include a secondary buffering system in addition to the primary display buffer, to assist in the support of pan, zoom and other navigation actions.
8.1.4 Coordinate Transformation Engine
Many clients have the ability to perform coordinate transformation. This service is relevant to all three map-creation functionalities: Feature Production, Imagery Production
and Exploitation, and Sensor Web Planning and Exploitation. The coordinate transformation engine is typically an essentially isolated entity within the application or
an external, dynamically bound library. It does not inherently support or require user interface elements, but it may receive parameters from user interface components used
for selecting transformations or target spatial reference systems. It may also report source and destination reference systems to a status display.
8.1.5 Rendering Engine
The rendering engine is the component of the client that converts data to a form in which it can be displayed graphically. The data come from remote services, including OGC data
services, and possibly local data stores. Styling information may be created or manipulated locally see below, or may be received from another source, possibly as a
standard styling document such as a Style Layer Descriptor.
Note that images retrieved from WMS servers are already styled, although it would be possible for a client application to restyle them via one-to-one color remapping or some
more sophisticated algorithm. However, raw data retrieved from WFS cannot be displayed unless they are rendered, with some sort of styling. Data from WCS may or
may no be displayable upon receipt, depending upon format and the client’s capabilities.
8.1.6 Style Editing and Management Interface
