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Measuring Green Speed with iOS Devices

February 21, 2012
 

 Marcus Jones, PhD, Iowa State University and
 Quincy Law, Graduate Student, Purdue University 

 

The iStimp App
By now, you have probably heard of the iStimp, an app developed by iGolfApps.com, to measure green speed. The iStimp is available to anyone who has an iOS device such as an iPod Touch, iPhone, or iPad for a nominal fee of $0.99. A stimpmeter reading is obtained by rolling a golf ball off the iOS device and measuring the distance the ball travels with a built in ruler. The iStimp application then uses algorithms to generate a stimpmeter value.

With over 250 million iOS devices sold to the public, the iStimp may have already appeared at your facility. If not, chances are you will at some point in the future. The question is, does the iStimp produce stimpmeter readings equivalent to what you generate with the USGA stimpmeter? A study conducted at Iowa State University set out to answer that question.

How we did it
Our study was conducted on a practice putting green at a local area golf course. The turf was a mixture of creeping bentgrass and annual bluegrass mowed at 0.125 inches.  Wind speed was negligible during the test.

Stimpmeter readings were obtained using the iStimp app with an iPad 2, iPhone 4, and iPod touch 4th generation. The USGA stimpmeter was included as a control along with a research stimpmeter which is known to produce equivalent stimpmeter readings.

Three people, each with varying experience using stimpmeters, operated each device. All accessories (cases, ect.) were removed from each iOS device with the exception of screen protectors.

A level area of the green was selected and a tee was inserted at the end of the measurement device. Three golf balls were released, one at a time, from each device according to the guidelines suggested by the manufacturer. Titleist Pro VI golf balls, each weighing within one gram of the others, were used in this study.

The distance each golf ball traveled was measured from the end of each device to the front of the golf ball. The built in ruler function was used with the iOS devices and a measuring tape was used to record ball roll for the USGA and research stimpmeters. This length was recorded for each golf ball and the average obtained. The same three golf balls were rolled in the opposite direction along a similar line and the same measurements and calculations performed.

Accuracy of the iStimp
The green speed of the putting surface was 12 feet according to the USGA stimpmeter (Figure 1). This device is the only tool accepted by the USGA to measure green speed. The research stimpmeter produced a statistically similar reading of 11.8 feet. Research stimpmeters have proven to yield green speed values similar to the USGA device. The fact that the USGA and research stimpmeters produced statistically similar values in our experiment verifies our technique.

The three iOS devices equipped with the iStimp app failed to produce stimpmeter values similar to the USGA device (Figure 1). The iStimp application when utilized on the iPad 2 underestimated stimpmeter readings by 9%. In contrast, the iStimp application overestimated stimpmeter readings on the iPhone 4, and iPod touch 4th Gen. by 21 and 16%, respectively.
 

Figure 1. Stimpmeter readings for five devices used to measure putting green speed.  Columns with different letter are statistically different.  Note: Stimpmeter readings are listed in feet: 14.5 = 14’6”.

If golfers approach you and want to discuss stimpmeter readings obtained from the iStimp, take the time to find out which device they used. While the iPad 2 generated readings most similar to the USGA stimpmeter, this seems the least convenient device to obtain stimpmeter readings with due to its size and expense. There are probably far more iPod’s and iPhone’s that find their way onto golf courses and each of these devices will overestimate stimpmeter readings.

Regardless of the iOS device used, stimpmeter readings obtained with the iStimp app on the iPad 2, iPod touch 4th Gen. and iPhone 4 are different compared to the USGA stimpmeter and comparisons are not valid.

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What's the Web Saying About Turfgrass: 8-27-10 Edition

August 27, 2010

This week brought a break from the rain and we were treated to cooler temperatures. It's looks as though things will heat up again next week. Until then, here are some turf and golf related thinks.

iPhone at Work: Certified Golf Course Superintendent. How does a golf course superintendent use his iPhone to get the job done and what iPhone apps help get him through his day? Here’s one superintendents answer and as a small token of thanks we’re sending him a $20 iTunes gift certificate. http://www.tipb.com/2010/08/11/iphone-work-certified-golf-superintendent/

Golf's biggest problem-Women may be solution. The overwhelming problem facing the golf industry is finding new players while retaining those who already play. Money and time have been spent to find a fix. Just not often enough to generate a pattern of growth rather than decline. The Right Invitation makes the case for additional investment in order to attract and retain women customers and that these women are the source of growth for the golf industry. http://frontpagegolf.com/News/News2010/Golfsbiggestproblem081510.html

The History of Golf Course Superintendents. This is a great video for anyone that loves Golf. As a matter of fact, it is great even if you don't like Golf, but would like to learn some things that didn’t know. http://golf-game-equipment.com/?p=945

Hey golf gods, what did Dustin Johnson ever do? This letter of complaint is for the gods of golf: Which one of you has Dustin Johnson ticked off? You've shown this kid no mercy. What next, the rack? http://www.usatoday.com/sports/columnist/lopresti/2010-08-16-lopresti-johnson-gods-of-golf_N.htm

Nuisance ants on golf courses. Mound-building nuisance ants have become one of the most troublesome pests in golf course maintenance. This article provides an update on our current USGA-funded research project concerning biology and pro-active management of turf ants on golf courses. http://usgatero.msu.edu/v02/n22.pdf

Enemy Number One to Black Cutworms. Superintendents can feel alone in their battles to protect golf courses from the ravages of insect invasion. They are not - Mother Nature is on their side. University of Kentucky entomologist, Dr. Dan Potter, and his talented group of graduate students, investigate how natural enemies of turf insects can help limit turf damage to golf courses. One such enemy is a type of virus that attacks black cutworms-and it works. http://turf.lib.msu.edu/gsr/article/nus-potter-8-9-10.pdf

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BASF launches free Turfgrass Disease App

November 11, 2010

BASF Professional Turf & Ornamentals is pleased to introduce a free Web application that gives U.S. golf course Superintendents quick, expert advice on turfgrass disease control programs via their mobile phone browsers. To use the tool simply visit the BASFTurfTalk.com blog or directly link to BASFTurfDiseaseControl.com on a mobile device, such as the iPhone®, Android® and Blackberry®, or desktop browser.

The tool gives Superintendents immediate access to disease control program recommendations specific to Northeast, Midwest, Transition and Southern regions and turf types. In addition to helping Superintendents control known diseases, it also helps them predict diseases based on the time of year or, in the case of the Southern region, based on soil temperature. The tool then recommends fungicide applications, timing and rates from Kyle Miller and Kathie Kalmowitz, Ph.D., the BASF Professional Turf & Ornamentals Technical Specialists who developed the disease programs.

“With a workspace averaging more than 140 acres, golf course Superintendents spend more time away from their desks than other professionals; yet their need for immediate, reliable information is just as pressing,” said Brian Lish, Business Manager, BASF Professional Turf & Ornamentals. “This new tool gets our expertise to customers when and where they need it to help them succeed.”

To view the tool’s functionality, watch the video demonstration and visit www.basfturftalk.com for detailed information and helpful instructions on using and bookmarking the Web app from your mobile device or desktop.

For more information about BASF Turf & Ornamentals, visit www.betterturf.basf.us or tweet us at twitter.com/basfturf_us.

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