How do I get the "Measurement Units" setting from OS X?

Question

I want my app to display measurements in US or Metric based on the chosen setting in OS X's International preference pane.

How do I get this piece of information from the OS in my code?

Answer 1

Use

BOOL usesMetic = [[[NSLocale currentLocale] objectForKey:NSLocaleUsesMetricSystem] boolValue];