If the plans dont state it categorically then you cant be sure. Your just guessing and not good enough. Even if they do state it dont trust it unless you know how they determined True North. People regularly stuff up reading a compass and make some arbitrary adjustment for magnetic north that can easily be wrong.
You really need to confirm it on the ground and then compare that to the plan. This has been covered here before
http://www.ata.org.au/forums/topic/10555
I recommend the method covered in the second post using the below web site and the shadow cast by a vertical pole/string etc.
http://www.ga.gov.au/geodesy/astro/smpos.jsp
Its a bit of a fiddle but accurate.
If you use Catopsilias GPS method that is only going to be accurate if your north and south boundaries are a long way apart
Posted Friday 19 May 2017 @ 12:47:02 am from IP
#