Golf Putting Charts

Putting Charts iPhone App

Want to improve your golf scores and handicap? The 'Putting Charts' App was developed for golfers like you to provide Aimpoint, Apex and Finger aiming, helping you read putts on sloping golf greens. It provides various selectable tables and charts, for aim point, apex and finger breaks, that can be adjusted for specific green conditions. 

Green reading predictions work best on putts inside 15ft, i.e. those with a higher make percentage. In many situations, these have a near constant slope along the putt line, and the break can be determined with reasonable accuracy.

For accuracy, and to adapt to specific conditions, breaks are calculated in real time on your device. Putt trajectories are determined for each putt by applying known ball motion physics for sloping greens.

From the menu, the table contents can be selected with "Aim Point", "Apex" or "Finger" break distances, from the "pin" or "hole edge", in inches or fingers. Aim Point variation can also be shown against slope, clock or stimp speed

Greater slopes, higher green speeds and smaller "past hole distances" will result in larger aim point breaks. If putt aim points breaks are shown in red then calculations suggest either the putt is marginally stable or the ball may not stop rolling after it passes the hole.

Putting Charts also offers Clock Angle as an additional adjustment for better precision. Clock angle is the angle from the fall line to the putt line. Most putting tables are set up assuming putts are cross hill, i.e. at 90degrees to the fall line. Often, this is simply corrected by adding a little more for downhill putts and a little less for uphill putts, than putting tables suggest, however, this can be expored further with the options in this app.

Measuring Green Slope

Measuring green slope is key to use putting tables effectively. With practice, some are able to measure slope with their feet, by feeling the weight difference while straddling the putt line, and some can assess by looking from different aspects around the hole. If you want to learn, buy an accurate digital level and experiment with it on different greens. Alternatively, for practice, consider using a slope measuring app on your phone e.g. Green Slope. 

In Putting Charts, slopes can can be set to use percent or degrees. For most people, percent is easier to assess and measure, e.g. a 1% slope is a one inch height change over a hundred inches. It's often easier to visualize percentage slope by realizing that 1% is about a half an inch change "over the length of your driver", and therefore 2% is one inch. and 4% is two inches.

Options

Break Tables

Buttons

Menu Settings

Aim Point

The Aim Point for any putt is a distance along a line perpendicular to ball to hole putt line, as shown in the diagram above. The line from the ball to the "aim point" is the putt's optimal starting direction, to ensure a putt at the right speed will fall into the hole (if hit with enough speed to travel the required distance past the hole). It can't be overemphasized that the "aim point" is not the "apex" of the putt.

It can take some practice to get used to the concept of starting a putt toward the aim point. From a technical standpoint, it's the intersection of the "tangent of the putt curve at the ball", projected onto the "line perpendicular to the ball to hole line"". More simply, it's the direction to start the putt to give you the best chance of getting it in the hole!

After selecting (touching) a putt break value in the table, the Graph button can be used to show the putt curve from above. On the graph, the Y axis represents the fall line (maximum slope line through the hole), with the X axis perpendicular to it (at a 90 degree clock angle from the Y axis). The graph will generally include both the aim line and apex to help understand the putt. Graphs are explained in more detail later.

Apex

Some golfers prefer to assess putts by visualizing a break line into the hole, and from experience they will estimate the maximum break off the line to the hole. This "break" is the "Apex" of the putt.

From typical break geometry, the break apex occurs a little more than half way to the hole, and has a value of about a third of the aim point.

Note that golfers who putt to the apex may instinctively putt below the necessary aim line. To effectively use apex break values, putts need to be aimed at a point about a third of the way to the hole.

Clock Angle

The angle from the fall line to the putt line is the "Clock Angle". A 90 degree clock angle is a putt perpendicular to the fall line. Anything less than 90 degrees is a downhill putt, and anything greater than 90 degrees is an uphill putt. Downhill putts require more break and uphill putts need less break.

Clock angle is measured from the fall line down. Since actions are simply mirrored on either side of the fall line, clock angle is always assessed in the 0 to 180 degree range. Left side putts will break "Left to Right" (L-R) and right side putts will break "Right to Left" (R-L).

"Clock Angle" together with Slope, Speed and selected Past Hole Distance, determines the break of any putt.

Putting Charts offers clock angle as an additional adjustment for better precision, and to help understand the effect of offset from the fall line. To use this, find the slope of the fall line (maximum downhill slope), and then estimate the clock angle to your ball. 

In many cases, golfers can simply compensate for clock angle by adding a little more offset on putts with more downhill slope and take some off for uphill putts. Clock angle may be more useful during practice, or simply when exploring the effect using the app.

Fingers

It has been noted that for many putts, aim point break from the pin can be approximated using fingers held at arms length. It's not uncommon to see professional golfers using this technique in competition. To help you with a measured assessment, that can be adjusted for circumstances, the break tables can be shown in "fingers", from the "Table Contents" selection in the menu. In use, you stand a set distance behind the ball, hold up a number of fingers equal to the green slope, and use that to locate the aim point offset from the pin.

To use fingers, stand behind the ball, looking along the putt line from the ball to the pin, hold up the required number of fingers up at arms length, put the pin on one side of your fingers, and your aim point will be on the other side of you fingers. Pick an appropriate point on the ground on the line from the hole perpendicular to the putt line. This will be your aim point.

To match individual needs, the width of your four fingers together can be adjusted in the menu, along with the distance from your eye to your fingers. Typically, hand width should be 3' to 4", and the eye distance should be about 20" to 28".

This technique is approximating the angle formed between the start line and putt line, with the equivalent angle formed between your eye and the edges of the fingers being held up. To make this accurate, you should adjust the eye distance in the menu for the length of your arm. If you want to be more precise with this technique you can adjust the distance from your fingers to your eye to somewhat compensate for green speed.

This is a little technical, but the technique matches the angle formed between the aim point direction and putt line, with the equivalent angle formed between your eye and the edges of the fingers. Using fingers for the break angle in this way, works best on the linear part of the slope v break curve. To improve the finger measurement approach, standing a set distance behind the ball, while holding up fingers, helps linearize the measurement, and better match fingers to percent, over a wider range of putt distances.

Hence some limitations and acceptance of the approximation, the aim point from the pin can adjusted to one finger width per percent of slope.

For 3.5" wide hand, with a stimp 10 green, a "behind ball" distance of 6ft will set roughly "one finger per percent of slope" for putt lengths of more than about 5feet. Reducing the stimp to 8 works better with 3ft back and increasing the stimp to 12 works with about 9ft.

Green Speed or "Stimp"

Green speed is usually measured using a USGA approved "Stimp Meter", which is a aluminum channel that is lifted to an inclination of 20 degrees, causing a ball to roll onto the green at a standard speed of 6ft/sec. Grass friction slows the ball after it rolls off the Stimp meter, and the distance in feet from the end of the Stimp meter to where the ball comes to rest, is a measure of the "Green Speed" or "Stimp" value. To measure accurately, it's evaluated using three balls in one direction, and then measured again in the opposite direction, with the final Stimp speed value being an average of all results in feet.

Each golf course decides on its green speed based a number of factors it can be anything from about 5ft to 15ft. Higher Stimp values mean faster greens.

On most golf courses you can get an idea of the likely green speed or Stimp from the Pro shop.

Finding Green Speed

Once you have a likely estimate for the green speed, you can often improve this on the practise green by choosing an area with a consistent slope of at least 2% and then making some putts from maybe 10 to 15ft, and measuring the resulting break relative to the aim point and apex in the tables. Compare with the App's estimated break, and then adjust the green speed to match the actual putt breaks. Remember to allow for the past hole distance when doing this! Sometimes it's easier to measure and compare the observed putt apex.

Experience suggests that slower greens can be less predictable, and that it's better to adjust green speed after making several putts on the same line.

Questions?

Contact eagolfe@gmail.com to get more information