I don't think I've ever put here how we measure our paddocks, and interestingly at the workshop they told everyone to use the same tool.
We had a print out of our map with paddocks marked with us, which was funny.
Anyway if you're in NSW the Dept of Lands have an online tool Six Viewer http://lite.maps.nsw.gov.au/
and you put your address in and then look at the tools, there's a measuring one... I'm sure everyone would work it out.
We used it when looking for land to see the council boundries, and other information. We could measure the distance to the sealed roads or other things... handy tool.
As well when looking we used maps.google.com.au to find dams and flashearth.com gave us a better and closer view of properties.