The objective of interoperation is to increase the value of information when information from multiple sources is accessed, related, and combined. However,
care is required to realize this benefit. One problem to be addressed in this context is that a simple integration over the ever-expanding number of resources
available on-line leads to what customers perceive as information overload. In actuality, the customers experience data overload, making it nearly impossible
for them to extract relevant points of information out of a huge haystack of data.

We cite architectural alternatives, as database integration, warehousing, and then focus on a three-layer, mediated architecture. In the interoperation
paradigm we favor that information merging is performed as the need arises, relying on articulation points that have been found and defined earlier. In many
applications geographical markers present such articulation points.

The architecture we presented allows multiple application hierarchies to be overlaid, so that the structure forms a directed acyclic graph from client to
resource, although the information flow is in the opposite direction. The complexity is still an order less than that implied by arbitrary networks, simplifying
composition both in terms of research and operational management.