Uncle Ho’s Hideout #2 – MGRS Coordinate Conversions

Campaign Series Vietnam | Uncle Hos Hideout

In Uncle Ho's Hideout series, David Galster shares some of his tips and techniques in scenario research and design for CS: Vietnam. 

Welcome back, Komrades!

Sometimes we find location information in the form of the MGRS or military grid reference system. And naturally, we may want to convert these coordinates to latitide and longitude, commonly known as geographic coordinates.

Fortunately, there are several good webpages that make this conversion online. One such webpage is “Legal Land Converter” Here is the link:



To use this site, the MGRS coordinates must be in the form 48Q YD 929072.

  • The first number-letter combination, 48Q is the Zone Code. Each zone is 6° by 8°, longitude by latitude.
  • The next two letters, column and row are sub-zones.
  • Finally, the numbers are always given in even numbered digits. The first half is “easting” and the second is “northing.”

In this example, 929 is 92.9 km east of the “Y” western boundary. The more numbers given, the more precise the location.

If the MGRS coordinates have the full form, then use the website to find the geographic coordinates. This is what the entry looks like:

Campaign Series Vietnam | Uncle Hos Hideout

In this case, the geographic coordinates are 16.32810°N, 107.74123°E.

A new screen in the webpage shows this information and provides links to Google, Bing, and MapQuest maps for convenience.

Sometimes, reports will only show the row-column letters followed by the grid digits. For example, in a list of firebases, only the MGRS coordinates: YD 929072 are given. In this situation, you can still do the conversion, but must first find the zone code. The Indochina area zone map shows these codes.

What if you pick the wrong zone code?

Fortunately, the way the MGRS is organized, a pair of row-column letters in one zone cannot be found in an adjacent zone.

For example, if instead of entering 48Q, we used 48P, the webpage would give an error message: 100K row letter = 'D' is not inside Zone '48P'. This may help avoid mistakes.

Campaign Series Vietnam | Uncle Hos Hideout

Indochina Zone Codes

This is one way to convert MGRS coordinates to geographic ones.


I don’t know whether Uncle Ho knew about the MGRS system, but if he did, he would surely have sent out spies to get as much information, and as many US military maps as possible!

In next episode of Uncle Ho's Hideout, I’ll provide a little explanation and background about what appears to be a strange code for PAVN unit identification. Until then!

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