The Report
The Highlights
Below are highlights from Dr. Vonderohe's Laser vs GPS research. We've added translations where necessary; these scientific studies can be confusing.
"Given the results of this discussion and my 35 years of teaching and research in surveying and mapping, I am not at all surprised that nearly all professional golfers use laser ranging on the golf course. I think laser ranging is the best technology for determining distances on golf courses. The great advantages of laser ranging are its simplicity and the fact that it yields yardage directly to the hole – the final destination of the ball."
Translation: Distance to the pin is the most important distance in golf because that’s where you’re trying to go.
"There must be clear line-of-sight from the GPS receiver to the satellites. So, tree canopies (an issue on golf courses) and other obstructions that block large portions of the sky can prevent reception from some or all of the satellites, either reducing accuracy or stopping measurements from being made at all. The accuracy of GPS-measured coordinates is also affected by receiver characteristics, atmospheric delays, clock errors, errors in the orbits of the satellites, and reflection of signals by hard surfaces (e.g., building walls) near the receiver. These things combine to produce horizontal accuracies of less than 7 meters (95%) in the devices used for golf."
Translation: GPS cannot provide you with distance measurements accurate enough for you to play your best. Most of the time the measurements are +/- 7 yards, but sometimes they’re more than that. How much more? You never know.
"
"
Translation: +/- 7 yards
"The accuracy of laser ranging is proportional to the measured distance. Medium distances are more accurate than long distances. Short distances are even more accurate. This is important and valuable in golf. The specified accuracy of Laser Link’s QuickShot device is ± 1%. This is with 98% probability. The corresponding 95% accuracy is ± 0.84%. Therefore, a measured 100-yard distance is accurate to ± 0.8 yards (95%), a 200-yard distance is accurate to ± 1.7 yards (95%), and a 300-yard distance is accurate to ± 2.5 yards (95%). The device displays the measured distance to the nearest whole yard."
Translation: Laser rangefinders get more accurate as the distances get shorter, while GPS will continue to be +/- 7 yards. When you’re 75 yards away, do you want to know that you’re 75 yards, or do you want to know that you’re somewhere between 68 and 82 yards away? (And remember, you’ve never once in your life gotten up-and-down out of that front bunker.)
"WAAS was designed to support high-precision GPS navigation of aircraft, not on-the-ground uses that can have significant problems with ground-level obstructions. WAAS satellites are “geostationary”. That is, they appear fixed in the sky with respect to points on the ground. Once again, there must be line-of-sight between a WAAS-enabled GPS receiver and at least one of the WAAS satellites."
Translation: WAAS has the potential to increase the accuracy of a GPS unit, but only under the right conditions. Mountains, tree cover, buildings, etc., can block the WAAS signal. If the handheld unit does not have “line of sight” connection with at least one of the WAAS satellites, its correction capabilities are ineffective. Remember, because your GPS says on the box that it is WAAS-enabled, this doesn’t mean that it’s always using a WAAS-corrected signal; it simply means it could use the signal if it were able to pick it up out of the air.
"Horizontal accuracies of targets digitized from maps vary widely depending upon the quality of the map and the ability of the person doing the digitizing to identify and point on desired targets. The horizontal accuracy of well-defined points on one of the most-readily available satellite image maps is 4.3 meters (95%). Targets such as the middle of a green or a lay-up area are not well-defined, especially if the green has an irregular shape, so their digitized coordinates will be less accurate than those of other points on the map."
Translation: The accuracy of the map plays a significant role in the accuracy of your GPS’s yardage approximations. The middle of the green to you might be different than the middle of the green to the person who made your map.
I see that Laser Link Golf offers different laser range finders. The new Red Hot finder features the ability to find distances to bunkers, hazards, etc. If the laser finder needs reflectors on the flag sticks to bounce the laser off of to get the distance, how can it detect distances to objects such as bunkers, water hazards and trees where there is no reflective device? Are these measurements then as accurate as those obtained on the reflective flag sticks?
The Golf GPS companies exagerate their accuracy — I know, I got one!