Dear Mr King,
Interesting post.
As architect my comment on no.1. is that the north arrow which we place
in drawings (at least the ones I place) are based on the North direction
on large scale survey maps supplied by planning authorities and on which
the drawing would be based.
Errors of 15 degree
I have been enjoying the comments on estimating wall declination,
especially those which have the ring of experience about them.
I am prompted to offer the following Consumer Guide to the
methods I have used over the years (and two I haven't). I
am sure that many readers will be able to add to m
