Talk:Military Grid Reference System

message: Anyone heard of Georef?  When I was in the Royal Observer Corps, many years ago, I remember we used "UTM" on some maps, which seems to be the Military grid reference system; co-ordinates (within Europe, say) were like "PQ 123 456".  But on other maps, we used a system I remember being called "Georef".  This had a similar notation — two letters to identify a major "square", then two or more digits to identify a point within the "square" — but was based on lat-long, not UTM; hence, the "squares" were curved-trapezoids.  You got the accuracy of lat-long with the convenient notation of UTM / British grid.  Now I can't find any info on Georef (which, if it really existed, sureley deserves a mention).  Anyone ever heard of this?  — Johantheghost 18:10, 2 December 2005 (UTC)
replies: text: OK, to reply to myself, I found some info, and we now have an article on Georef. — Johan the Ghost seance 11:21, 17 February 2006 (UTC)
thread_title:  Georef? 

message: This makes no sense whatsoever. Anyone care to explain? How does someone have a legitimate lat and long and not know where on earth it is?! RobertDahlstrom (talk) 21:49, 7 May 2008 (UTC)
replies: text: I too am confused about why a different coordinate system cannot indicate the same location.  Seems to me (an ignorant layman) that it would depend instead on whether they use the same datum.  Or is there a rule that says that's not allowed?  Jim.henderson (talk) 01:56, 18 January 2011 (UTC)
thread_title:  What datum? 

message: I see no link to "point reference system" nor article by that name.  Is the concept explained in another article, or should the distinction between that and other systems be explained in this one?  Jim.henderson (talk) 09:29, 16 January 2011 (UTC)
thread_title:  point reference system 

message: The article not explains neither point to a source about.— Preceding unsigned comment added by 179.208.229.37 (talk) 14:38, 1 September 2013 (UTC)
replies: text: It means Square ID. Also, sign your posts in future using "~~~~", so that we know who we're talking to. –  Nohomers48 (talk • contribs) 20:51, 1 September 2013 (UTC)
thread_title:  What is a SQ_ID? 

message: From the article:
:Related to this is the primacy of the southwest corner of the polygon being the labeling point for an entire polygon. In instances where the polygon is not a square and has been clipped by a grid zone junction, the polygon keeps the label of the southwest corner as if it had not been clipped.
I've been researching MGRS for a few days, but the above is totally opaque to me.  Does this have something to do with the fact that locations that border GZJs are canonicalized by some software libraries (e.g. 17SKT --> 16SGB5807198790)?  We should clarify the above with an example.  Ericbg05 (talk) 13:39, 10 June 2014 (UTC)
replies: text: It's talking about how some squares like 18N SF don't have a 0,0, easting,northing as the southwest corner is outside of the zone. It's because of UTM. The squares are square in reference to the equator, and the vertical "central meridian" line in the centre of each zone.https://en.wikipedia.org/wiki/Universal_Transverse_Mercator_coordinate_system#Locating_a_position_using_UTM_coordinates In UTM, that line is 500,000 easting. 0 easting doesn't exist, it's in the zone to the west. So in MGRS/USNG, the squares on the edges of zones are clipped, but the squares on the west side still use the soutwest corner for 0,0 easting,northing, even though that's a possibly invalid point. I might try to clear up the article, but I want to do more work with USNG/MGRS first to ensure my understanding is correct.  Mtfurlan (talk) 16:32, 27 October 2016 (UTC)
thread_title:  Sentences on clipping and labeling are confusing 

message: Referenced by this converter, where the coordinates match the lat/lng to MGRS conversion done by a different converter.
This book also references it, but I'm not buying the book to look at the books reference.
I'm not going to edit the actual article without a better reference than a google books link to a book whose sources I can't check.
Mtfurlan (talk) 16:19, 27 October 2016 (UTC)
thread_title:  Also referred to as "NATO UTM" 

message: I don't know why some zone starting with zero numbers and some zone starting with the numbers 6 (starting point). 27.109.113.245 (talk) 08:55, 20 May 2023 (UTC)
thread_title:  How coordinates of the joint of grid zone was made?