NGR (GRID REFERENCE)
The only grid reference that you definitely need to plot is that of the overnight campsite at the spring event. This is issued at the 'give-out' on Saturday morning. It is also helpful if you can learn to plot and read grid references in the event of an incident or for the use of GPS - which is allowed. A good knowledge of accurate grid reference plotting and reading is therefore a plus, and a waterproof pen will come in handy. Plotting grid references always causes some confusion, even with the best teams if done in a hurry! At every event, teams look for the overnight campsite at their wrongly marked grid ref! Double check your plotted positions before you start as this saves arguments and heartache during the event! Although the maps are pre-marked with the checkpoints and grid lines, we do not supply checkpoint grid references. We give an unambiguous description for the checkpoint (control). If you use a GPS co-ordinate it may have too much precision to be usefully correlated with grid references and control descriptions on the ground. Don't forget that 100m2 on the ground is 2mm2 on a 1:50 000 OS map and 4mm2 on a 1:25 000 OS map. A map roamer will help with your plotting of the grid references. In reality, we strive to overprint the checkpoints on the map very accurately, and the vast majority of teams do not refer to grid references at all.
