dale182
Member
Hi all,
Can someone please clarify what property title plans are referencing.......true north or magnetic north?
Also...when reading house plans is the north point to true north or magnetic north?
Would be great if someone in the industry can clear this up for me and perhaps direct me to some literature to confirm.
Cheers
Dale
Hi Dale
At least in parts of NSW, bearings on property plans refer to magnetic north as it was at some date in the past. That date may be hard to find out.
House plans should show true north, as there is no longer any point in using magnetic north. Don't expect accuracy within 30 degrees though.
You can establish a true north-south line on your property using a hand-held GPS. Drive a peg in on the south boundary. Read and note down the longitude on the GPS. Go to the north boundary, walk along it until the GPS reads the same as before. Drive a peg in there.
You could pay a surveyor to do much the same thing when laying out the site for your house.
arttt
Member
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
