Hi Richard, any relation to the punch card guy ? IBM paid my salary for 35 years. Someone in one of these threads got squashed flatter than a pancake for supposedly confusing maps and territories, so let's be careful with models of reality. When I say 'dependant on usefulness', I just meant that the selectivity and level of detail of the map would depend on what you want to use it for. Not much point in going to the doctor and telling him the 'truth' about my finger, which would involve energy fields and dark matter, if what I want from him is a sticking plaster. Lovely article here on what the Romans thought was important in a map, and why it doesn't look like one that we'd find useful, or 'truthful', today. http://news.bbc.co.uk/2/hi/europe/7113810.stm