International Team Scans Entire Mount Rushmore in 3-D

Entire monument and surroundings scanned to subcentimeter accuracy.

Published: Thursday, May 27, 2010 - 06:00

It took Gutzon Borglum 14 years to complete the carving of Mount Rushmore, one of the world’s most iconic monuments. Sixty-nine years later, thanks to ground-breaking 3-D laser scanning technology, the granite sculpture of Presidents George Washington, Thomas Jefferson, Theodore Roosevelt, and Abraham Lincoln was digitally recreated within two weeks, despite difficult weather conditions—snow, fog, and thunderstorms.

From May 11–26, a team of heritage conservators and digital design experts spent hours on the Black Hills of South Dakota digitally recording the international landmark, including the Sculptor’s Studio, the Hall of Records, and the Shrine of Democracy sculpture. The mission is part of the Scottish 10, an ambitious five-year project that will use 3-D scanning to recreate five UNESCO World Heritage Sites in Scotland and five international heritage sites, with Mount Rushmore as the first international site. World Heritage Sites are places designated by United Nations Educational, Scientific and Cultural Organization as sites of special global cultural or physical significance.

The cutting-edge project will provide realistic digital information of the scanned sites, which could be used as an educational tool or long-term preservation management, as is the case of the Orkney Islands and Skara Brae in Scotland, where sea-level changes and coastal erosion are a concern. In the case of Mount Rushmore, if an event that damaged the sculpture was to occur, for instance, the data would provide crucial information to accurately replicate carved surfaces. In addition, the digital data would also allow experts to develop 3-D modeling virtual tours of the site.

The team working on Mount Rushmore’s 3-D scanning was comprised of members from the National Park Service technical ropes team, scanning specialists from the Kacyra Family Foundation and their project CyArk, Historic Scotland, and the Glasgow School of Art, as well as local technical consulting staff from Respec Engineers Inc., Wyss and Associates Inc., and the South Dakota School of Mines and Technology. The team used Leica Geosystems’ Leica Scanstation 2, Leica HDS6100, and Leica Scanstation C-10, to perform the scans, according to Douglas Pritchard, from Glasgow School of Art’s digital design studio.

Members from the Mount Rushmore National Memorial technical ropes team work with a custom made tripod to get a detail scan of Theodore Roosevelt’s eyes. (Photo by Amy Bracewell)

The scanning data that has been captured is the first highly accurate and comprehensive survey of the mountain. Leica’s 3-D laser scanners are able to capture more than 50,000 dimension points per second.

“We expect to get complete contours of the presidential faces and surrounding rock faces, and the talus slope and vegetation down to a subcentimeter level of accuracy. In addition we will have complete geo-referenced photography,” says Pritchard.

To collect the data, the team had to get as close as 10 mm from the surface of the monument, a task that’s particularly challenging, given the mountain’s 5,725-foot altitude.

“The size of the monument and the surrounding irregular terrain were some of the unique challenges of this project," Pritchard adds. “Obviously, getting up onto the heads and the edges of the Monument Valley is, too. Another current challenge is the irregular weather.” South Dakota’s weather in May can still be snowy and rainy.

“The challenge at Mount Rushmore was in covering all the angles, so we had to get up and onto the chins of the presidents,” Historic Scotland’s technical conservation group director, David Mitchell, told BBC News.

(Photo by Amy Bracewell)

During the first week of the project, the team completed the digital scans of the interior and exterior of the historic Sculptor’s Studio, the Hall of Records behind the sculpture, and several perspective scans of the Mount Rushmore sculpture. Scanning stations were set up behind the sculpture to get the top of the heads, as well as stations along the Presidential Trail to scan the front of the faces. In addition, a scanning tripod was custom made to capture scans directly on the mountain.

At the end, the team was able to capture a large amount of data that will be processed in the coming months. Data processing will take between 10 to 12 months and entails the merging of all the separate scanning locations, matching up data points, confirming the accuracy of the data, and overlaying photo texturing for a real-life effect. Once the processing is complete, the memorial will begin developing park programming using the laser scanning data. Application of the data can include virtual tours, 3-D models, digital animations, and interactive programs.

One day perhaps, people will be able to look at the monument and surroundings from George Washington’s 20-foot nose and take in the majestic view of the Black Hills with a brand new perspective. They won’t have to hang from a rope to do it.

Scanning locations on the Presidential Trail, the top of the sculpture, and even scanning directly on the faces captured millions of data points to create a highly accurate digital record of Mount Rushmore National Memorial. (Data image by the Kacyra Family Foundation)

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Raissa Carey