|
|
Subject: Re: Mercator vs. Great Circle Charts
From: Carolyn Seefer (CCSeefer@XXX.XXX)
Date: Wed Aug 29 2001 - 12:24:07 EDT
In a message dated 8/29/2001 9:05:39 AM Pacific Daylight Time,
navsys@XXX.XXX writes:
> The question is unclear to me. What is meant by "true direction"? Is
> this the course to be steered or just a bearing?
My guess is that "true direction" in this case means if one can gauge
N-S-E-W just by looking at the chart. When I look at the Mercator chart, it
seems as though I can tell directions accurately, and all compass roses on
the chart are identical. With the great circle chart, on the other hand, the
distortion seems to also distort the actual directions. Just by looking at
the chart, I can't actually determine what is "true North." It seems that
adjustments would have to be made. Again, I'm new to all of this!
By the way, thanks for pointing me to the NIMA publications online. I've
already started reading Chapter 3 of the Bowditch text. This is very helpful;
Bowditch hasn't been mentioned in class yet.
Carolyn Seefer
|