Message-ID: <000f01c51e5e$ba9170a0$2101a8c0@AUG2004>
From: "Walter Blanchard" <blanch@pncl.co.uk>
To: rsgb_lf_group@blacksheep.org
References: <200502271724500058.0418698B@mail.zetnet.co.uk><005001c51cf8$524d6c40$10b80150@p2300> <200502281113330523.07EADBD4@mail.zetnet.co.uk> <007201c51d8c$ab993a60$37b80150@p2300> <004101c51e54$11e9fa80$2101a8c0@AUG2004> <003d01c51e5a$7da54440$47540150@p2300> <005501c51e5c$5170d220$47540150@p2300>
Date: Tue, 1 Mar 2005 13:01:02 -0000
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Subject: LF: Locators
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>> That is an interesting historical account but you fail to tell us the
>> reasons advanced for not using Lat. Long. ie trigonometrical definitions
> on
>> a true curved surface rather than  draughtsman drawn squares on a
>> draughtsman drawn simulation on a flat sheet of paper
>>
>> G3GVB


Seems to be some misunderstanding here. QRA, Maidenhead,GEOREF are all based 
on lat/lon anyway and are true geographical referencing systems. Their 
boundaries, squares etc are all derived directly from lat/lon; they're 
simply attempts to make it easier to describe a lat/lon position without 
using continuous strings of numbers. What you're thinking of are GRID 
systems such as the OS's National Grid Reference (NGR) which are indeed 
drawn on a flat sheet of paper specifically because they're a lot easier to 
use on paper maps and are designed ONLY to be used on maps. Navigators do 
not use NGR for navigation - as you will know if you're a sea captain. 
Grids can only be used over relatively small areas such as the British Isles 
because they get so much out of sync with the real world over large areas 
they become unusable. That's why the USA does not use a true grid system 
like NGR. Incidentally lat.lon uses SPHERICAL trig. relationships.

Walter G3JKV.