Is there a network map of subjects and how they connect with each other? The problem

When doing a literature review at the start of a process of addressing a specific problem, it's easy to miss related material, if I don't know that it is related.

The example

Let's say I'm looking at a particular electricity-generation  problem relating to pollution costs (in a very broad sense), of combustion and cooling: there might be relevant papers about,  say, biodiversity and temperature in river water, that I don't know about, and haven't made the connection to, and it appears in a journal well outside the field of electricity generation.

However, within the literature, there will be authors whose papers span those fields: work on valuing biodiversity (so that loss of biodiversity represents a quantifiable cost), and the effect on biodiversity of changing river temperatures (so that using river-cooling in electricity generation, has a deleterious effect on river biodiversity).

The proposition

It should be possible, by doing an analysis of keywords, of co-authorship, and of journals, to automate the building of a network of subjects and of authors, to map out interconnections between specific narrow subject areas, and find the people that work in those interconnecting areas.

The question

Is there such a network map of subjects and authors, anywhere? Not just for this specific example, but one that spans a very wide range of literature (e.g. Engineering, Science, Technology, Economics). Ideally, one that gets updated frequently, based on ongoing publications?

As I hope the example above illustrates, it has to be:


easy to interrogate it;
very detailed on subject linkages; and
provide links between people as well as subjects.
Here is a subject map of science:



It is taken from the following paper, freely available from Plos One:

http://www.plosone.org/article/info:doi/10.1371/journal.pone.0039464?imageURI=info:doi/10.1371/journal.pone.0039464.g001

I think that this is the sort of thing that you are interested in. 

N.B. I am not a co-author, nor have I read the paper, so I make no judgment on its quality.