Coordinate systems

content/docs/entertainment/games/args/index.adoc

@@ -71,6 +71,20 @@ Country code top-level domains:: https://en.wikipedia.org/wiki/List_of_Internet_
 Country calling codes:: https://en.wikipedia.org/wiki/List_of_country_calling_codes
 Timezones:: https://en.wikipedia.org/wiki/List_of_tz_database_time_zones#List
 
+==== Coordinate systems
+
+[%header]
+|================
+| Name | Example | Tools
+| Latitude/Longitude | `52.4542427,-1.7192038` | https://www.google.com/maps/[Google maps]
+| Eastings and Northings | `419008E 283712N` | https://gridreferencefinder.com/[Grid reference finder]
+| National grid ref | `SP 19052 83959` | https://gridreferencefinder.com/[Grid reference finder]
+| Plus codes | `F73M+M5 Marston Green` | https://www.google.com/maps/[Google maps]
+| Mapcode | `GBR 4HH.B70` | http://www.mapcode.com/[mapcode.com]
+| Geohash | `gcqf2vh05ese` | http://geohash.org/gcqf2vh05ese[geohash.org/<hash>]
+| What3words | `//filed.trial.manual` | https://map.what3words.com/[what3words.com]
+|================
+
 ==== Transportation codes
 
 IACO:: https://en.wikipedia.org/wiki/ICAO_airport_code#Prefixes