Military Grid Reference System: Difference between revisions

Revision as of 06:02, 21 March 2022

Revision as of 17:25, 16 May 2022

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For the row letters, there are actually two alternative lettering schemes within MGRS:

* In the ''AA scheme'',<ref name="MGRS_Final_Guidance">

[http://earth-info.nga.mil/GandG/coordsys/MGRS_Final_Guidance.doc NGA Guidance for the Military Grid Reference System (MGRS).]</ref> also known as ''MGRS-New'',<ref name="Military_Map_Reading_201">[{{cite web|url=http://earth-info.nga.mil/GandG/coordsys/mmr201.pdf |title=Military Map Reading 201]|archive-url=https://web.archive.org/web/20210224185834/earth-info.nga.mil/GandG/coordsys/mmr201.pdf|archive-date=February 24, 2021}}, published by [[National Geospatial-Intelligence Agency|NGA]]</ref> which is used for [[WGS84]] and some other modern [[datum (geodesy)|geodetic datum]]s, the letter for the first row – just north of the equator – is A in odd-numbered zones, and F in even-numbered zones, as shown in figure 1. Note that the westmost square in this row, in zone 1, has identification AA.

* In the alternative ''AL scheme'',<ref name="MGRS_Final_Guidance"/> also known as ''MGRS-Old'',<ref name="Military_Map_Reading_201"/> which is used for some older [[datum (geodesy)|geodetic datum]]s, the row letters are shifted 10 steps in the alphabet. This means that the letter for the first row is L in odd-numbered zones and R in even-numbered zones. The westmost square in the first row, in zone 1, has identification AL.