The System Landscape Directory (SLD) of SAP NetWeaver 
serves as a central information repository for your system 
landscape. A system landscape consists of a number of 
hardware and software components that depend on each other 
with regard to installation, software updates, and demand 
on interfaces.

The exact meaning of landscape is the different types of
servers systematically arranged in the system landscape
directory.
landscape refers to the kind of systems in place. more
simple: dev sys, quality sys, prod sys and a sandbox.

The legacy systems which are registered with the integration
server to exchange business information with the SAP system
also come into Landscape.
So landscape varies from company to company.

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