Join Date: Mar 2005
Location: Calgary, Alberta, Andorra.
Interest: hiking, backpacking, scrambling, climbing
I believe the newest KCTC edition now uses NAD 83, but the older ones (the 2-book 3rd edition from 1995ish) used NAD 27, which became REALLY outdated along the way.
If you have 11 U easting: 0670909 northing: 5615281, then you pull the relevant digits of:
easting: 06(709)09 and northing 56(152)81,
which condenses to a 6-digit grid reference of:
You will also see this called Military grid references, as it is based on the common practice.
You would never condense it to GR7090915281. That would be a number no-one has any clue how to parse.
You either use the full references, or the 6-digit.
The GR you quoted has only 5 digits, which would again not be used. If it was, for example GR071648, then to put that in your GPS, you would pull out the relevant information:
easting: __071___ northing: __648__.
The end digits, you just zero: ( __07100 , __64800 ), and to get the front digits, check on your map for what's in the area. (probably an 06 or 07 for the easting, and a 56ish for the northing).
If you look at a map, it makes more obvious why we use the three significant digits, since the map UTM grid usually only shows two significant digits, dropping the front ones, and and we guess the 100m based on battleshipping the point within the 1km square.
So just make sure that you set your GPS to the datum your map or book is using, and you're good. You can even use the GPS to convert datums if your book and map are different, but with the new KCTG, you should be fine.
And oh, while we're talking datums, be aware that for recreational activity around here, NAD 83 is functionally equivalent to WGS 84.