1st Facebook Scout Group:
"Let's suppose I do not have a rope long enough, but just a stick/small rope, even smaller than the half of the long one. I set it at one end, perpendicular to the pole, and mark the point (usually, leaving a scout standing there). I do the same thing at the other end of the pole BUT ON THE OTHER SIDE. The imaginary line between the 2 scouts cuts the pole in its middle. Thus, when the Scouts see me on the line between themselves an their opposite pal while I walk along the length of the pole, I have found the middle.That's it ! The longer the pole, the longer the stick, the more accurate."
These three methods are all variations on direct measurement - measuring with a rope and folding the rope in half, using a tape measure and halving it, or pacing out with a shoe, a shorter stick, a ruler or any other item.
drawn on iPad Mini using Paper app and Just-Mobile AluPen