New York - The scale of putting-green maps, including those on electronic devices, will be limited under rules announced Monday by golf's governing bodies, the Royal and Ancient Golf Club and the US Golf Association.
The new interpretation of Rule 4.3 will come into force on January 1, 2019, and follows a six-week feedback period on plans to make the change.
"It's important that we take steps to ensure that skill and judgment are the main determinants of success in reading the greens," R&A executive director for governance David Rickman said.
"We received some extremely useful feedback over the last six weeks that helped us finalize the limits."
The rule will limit detailed green maps used by golfers during a round, including those on electronic or digital devices, to a scale of 3/8 of an inch to five yards (1:480) or smaller while a notebook or paper map image must not be larger than 4.25x7 inches.
A hole location sheet displaying nine or more holes on a single sheet of paper can be larger provided images of individual putting greens meet the scale limit.
The move is meant to reaffirm the USGA and R&A view that reading greens is a crucial golf skill.
"These latest modifications provide very practical changes that make the interpretation easier to understand and apply in the field," said Thomas Pagel, USGA senior managing director for governance.
No magnification of putting green information is allowed other than normal prescription glasses or lenses.
Hand-drawn or written information about a putting green is only allowed if contained in a book, or on paper, that meets the size limit and was written by the player or the player's caddie.
Digital or electronic putting green maps will violate the rules if they fail to comply with the size and scale rules or if the device produces a recommended line of play based on the ball location.
"The new interpretation is a first step in the process and we will keep green-reading materials under review in 2019 to assess whether any further action is required," Rickman said.