Examples, you can have a look at flood maps (e.g. http://bit.ly/29BrBRI). Contraint maps can also simply be scribbly annotation on geographical maps — for example for noting noisy areas or views of interest.

Visualising the service ecology is more of a challenge, because we don’t simply have a geographical grid to build on.

Things like stakeholder maps or service blueprints work (see http://www.servicedesigntools.org/taxonomy/term/8) but I think also things like domain models could have their place there (http://schleith.org/projects/music-events#domain-model).

Fabian Segelström wrote some interesting things on visualisations in Service Design (http://segelstrom.se/#publications)