Photogrammetry—Fossils in 3D

Structure-from-motion

Structure-from-motion (SfM) photogrammetry is a means to digitally document the surface details of an object in 3-dimensions using off the shelf cameras, computers and software. Photogrammetry historically has been used to measure details on the surface of the Earth, structures or other natural features. Employing SfM, like traditional photogrammetry, surface details and the dimensional aspects of even small objects can be precisely measured and digitally archived for future study. For paleontology, this method in recent years has increasing become important because the costs with recording an object are continuing to drop and easier to use as technology improves. SfM has broad applicability in paleontology for both body (think bones and teeth) and ichno- or trace fossils (think tracks, burrows or impressions). Additionally, the ease of transmitting the derived 3D data has allowed information on rare specimens to be shared with researchers and the public. The National Park Service uses photogrammetry to improve access to scientifically important or interesting objects and in turn enhance the visitor's experience (whether in-person or "virtually").

Grand Canyon—Ichniotherium trackway

Left image
Fossil trackway model with true color overlay.
Credit: NPS image by Jack Wood.

Right image
Fossil trackway model with color ramp overlay.
Credit: NPS image by Jack Wood.

Ichniotherium tracks found within the Grand Canyon are important clues to how early tetrapods colonized land. These tracks are especially important because the Coconino Sandstone was deposited as an erg and characteristic of a desert environment during the Permian (~280 million years ago). To help scientists, photogrammetry data can be used to create a map of the tracks, also known as a "heat map", which uses color to represent the changing  height of the surface features. Here, lowest areas are in blue and the highest are in red. Using the true color and the heat map together, the walking behavior of the animal can be better understood.

The Geologic Resources Division (GRD) of the Natural Resources Stewardship and Science Directorate has acquired equipment and software to develop a photogrammetric data program to support parks and regions. This includes technology and training for photogrammetric capture, analysis, and 3D printing, in the resource management areas of protection, research, mitigation, restoration, inventory, monitoring, interpretation, and planning. For more information on photogrammetry techniques and applications, contact us.