by Mark Sweeney
There is a long-standing concept about green-reading which never seems to die that is sometimes called the Single Point of Aim Theory or the Spider. It’s a simplification of Templeton’s concepts which attempted to find a point of aim located on the fall line above the hole rather than perpendicular to the line of play. However, as Templeton points out in his original work, in actuality there is no single point of aim, but rather the aim point moves up the fall line as the putt location moves from below the hole to above the hole. He called this “elastic gravity vectors” and they can be very complicated to calculate. As I will show here, this Single Point of Aim theory can be easily dis-proven mathematically and has almost no practical value on actual putting greens.
If you imagine a completely flat surface, every putt around the hole would be aimed directly at it, thus having a single point of aim. However, as we introduce tilt to the green, the points start moving apart. If we take the known breaks from around the hole (on a tilted but perfectly planar surface) and extend the aim points all the way to the upper fall line, the Single Point of Aim theory claims they will still all intersect in the same spot, as in the image below. These five 20-foot putts (at stimp 10) would all be aimed at the black dot labeled “Aim Spot”.
But in reality when we apply this concept to the true, known breaks for these five different putts, the actual aim points are all in different locations above the hole and look like this:
Notice the downhill putts are aimed significantly higher up the slope than the uphill putts, and this should not come as any surprise since downhill putts break more than uphill putts. And as we increase green speed and the amount of slope, the uphill and downhill aim points will continue to expand further and further apart. At stimp 12, 4% slope, the highest aim point is as much as 7 feet above the lowest point.
From a practical usage stand point, I tried using this theory on my putting green at the Waldorf Astoria Orlando on three standard pin locations. The reality of putting greens is that there are no perfectly planar areas to begin with. One side is typically steeper than the other side, and the fall line will almost always curve through the hole. The test was to simulate five putts from around the hole and see where their aim point would intersect the fall line above the hole. Here is the setup of the putting green and the 15-foot putts chosen.
Looking at pin 1 on the lower left, the spot where the aim points intersect the fall line are colored as purple crosses. The highest one is about 13 feet higher than the lowest one:
Here is pin 2, notice that there are only 4 intersections shown, because the blue putt never intersects the fall line due to its bend to the right through the hole:
And pin 3, again, the green putt never intersects the upper fall line, if you aimed there you would get the direction of the putt wrong:
What we can clearly see in these real-life examples is that the Single Point of Aim theory is useless as a predictor of break around the hole. Not only because the math doesn’t allow for it, but also because real golf greens, as opposed to hypothetical ones, have changing slopes around the hole. If you want to be a great green-reader, learn to evaluate each putt by itself based using the concept of side-slope along the line of play. It will be dramatically more effective and will not ever give you the wrong direction.