LOP's
Subject: LOP's
From: bhudson (bhudson@XXX.XXX)
Date: Wed Jun 23 1999 - 18:13:34 EDT
>Date: Wed, 23 Jun 1999 09:12:43 -0700
>To: Navnet
>From: bhudson <bhudson@XXX.XXX>
>Subject: LOP's
>
>Hi,
>All LOP's of a celestial nature need an arrow at each end. This is
>perhaps not so important with say a single sun observation but when
>it comes down to a multi star/planet set of observations (as many as
>six or maybe more) you need to distinguish the azimuth lines from
>the Position lines by placing the arrows.What a clutter we have if we
>dont do this. Electronically of course only the PL's appear on the LCD so
>it does'nt matter about the arrows. Someone already mentioned that
>the celestial PL is an arc of a circle and harking back to coastal nav
>when taking a sextant or radar distance off it is part of a circle of
>position so we put an arrow at each end of that arc of the circle we
>are most likely to be on. In coastal navigation we also have other
>arrow symbols to identify lines on the chart and prevent confusion e.g.
>is it a course line, bearing, tide or current drift,and so on. It is
>also important to bear in mind how many people are involved in the
>navigation of the vessel.For instance take a large commercial vessel
>with many users of the same chart one has to be particular with symbols
>used they must be readily understandable to all. In the case of a
>single navigator then he can do what he wants as long as the PL's make
>sense to him.
>Myself if I did'nt use arrows to distinguish between azimuth and PL
>confusion would rain supreme.
>This is a most stimulating network.
>Barrie Hudson
>
