An RFS 6 digit grid reference, is a fast and simplified way of communicating locations within a known operations area of 100kmx100km.

This simplification involves removing the unnecessary details (to the local operation) of accuracy and the broader location.

When mapping a 6 digit grid reference the specific 100x100km area it applies to is not know from just the 6 digits. Therefore we map all possibilities (for each blue grid), and you must work out which one is the most likely due to the location the report came from.

One way to get a 6 digit reference: start with a full UTM grid reference off a map and: For the Easting, take the 2nd,3rd & 4th digits, and for the Northing take the 3rd, 4th & 5th digits.

GitHub Project Page: https://github.com/bitsinaction/RFS_Grid_Ref_Map/

Thanks to Javier Jimenez Shaw, for his library:

Simple UTM (WGS84) methods for L.LatLng: https://github.com/jjimenezshaw/Leaflet.UTM

More Details:

https://nswrfs.atlassian.net/wiki/spaces/TECHNICAL/pages/44666448/Reading+a+Map

https://www.maptools.com/tutorials/grid_zone_details