By Deidre McCarthy, Richard O' Connor, and Catherine Lavoie

In honor of the 2016 anniversary of the National Park Service (NPS), Preservation Leadership Forum is hosting a series of blog posts highlighting its programs and history. In these posts NPS staff look back and on how far the Service has come and forward to where it hopes to go in the future.

The National Park Service (NPS) is dedicated to finding new avenues to collect more complete and precise data and share them with stakeholders at all levels. Incorporating technological advancements can make data easier to collect, store, and share with the public. Programs at NPS have evolved considerably in recent decades and are looking forward to more changes as our digital age brings increasingly rapid technological growth and expansion.

Rendering of the Contagious Disease Hospital Office Building on Ellis Island. | Credit: HABS, National Park Service

GIS and GPS

The cultural resource geographic information system (CRGIS) facility of the NPS originated in the early 1990s, primarily creating maps of Civil War battlefields for the congressionally mandated Civil War Sites Advisory Commission. At that time, GIS was not typically used to inventory or manage cultural resources, and civilian GPS technology was in its infancy. Applying these tools to the Civil War battlefield survey was groundbreaking and led to the creation of the American Battlefield Protection Program grants, new battlefield landscape survey methodologies, and the protection of many acres of battlefields that were identified through the assessment of significance combined with more accurate location of battlefield features.

National Register of Historic Places web map application available to the public. | Credit: National Park Service

The use of GIS and GPS technologies has grown exponentially since then—they are now part of every element of cultural resource management, resource documentation, disaster response, and more. Every State Historic Preservation Office (SHPO) now has a GIS-based inventory of their resources. Standard survey and inventory projects of all scales require GPS to locate features and GIS to manage data. Federal, state, and local agencies now consider these tools necessary to steward and protect cultural resources. CRGIS leads the way in exploring the application of these technologies to cultural resource management by developing standards that facilitate data exchange, creating web applications to expand access to data, and building NPS-wide datasets to better steward our resources.

GIS and GPS technology advance every day, offering more exciting methods and tools—and different ways to apply them to cultural resources. The biggest forthcoming trends are mobile technologies to enhance resource surveys and web-based tools to access GIS data for interpretation, documentation, inventory, and disaster response. As we search for ways to manage resources in the face of climate change, we can expect to see broader use of drones; 3D modeling; and the expansion of more user-friendly, yet technically advanced, GIS functionality through web platforms.

Battlefield landscape map showing Fort Foote, one of the Washington, D.C., circle forts. | Credit: National Park Service

HABS/HAER/HALS

In the more than 80 years that the Historic American Buildings Survey (HABS)—later joined by the Historic American Engineering Record (HAER) and the Historic American Landscape Survey (HALS)—has been in existence, its role in the production of documentation has changed little, but the tools used in the process have changed considerably. HABS/HAER/HALS continue to record America's architectural, engineering, and landscape heritage by producing measured drawings, large-format photographs, and historical reports of historic sites and structures. However, sophisticated tools like laser scanning, photogrammetry, and 3D modeling have recently come to supplement traditional hand measuring. The need for greater accuracy, reduced field time, and tools to aid conservation and interpretation, among other factors, drive the use of new technologies. The bar has also been raised for the written reports, which are increasingly expected to develop a more complex and nuanced historical context.

Exterior of the Contagious Disease Hospital Office Building on Ellis Island. | Credit: National Park Service

New technologies create both opportunities and challenges—they are a constantly moving target that demands field testing to keep equipment and software up to date and ensure best results. Each documentation project is different and requires different tools. For example, laser scanning is particularly helpful in recording large-scale sites and those that are potentially unsafe, while sculptural objects and details are more accurately recorded through photogrammetry. And despite the value of these technologies, hands-on measuring and analysis by trained architects is still necessary to fill in the inevitable blanks left in digital imagery and to gain a thorough understanding of any site. Laser scanning saves time in the field, but those savings are offset by the increased time required to post-process data and translate it into drawings using computer-aided drafting.

Digital information has allowed HABS/HAER/HALS to expand the interpretative tools they offer and create 3D models and virtual tours, which are particularly useful for sites and structures that cannot be easily visited. Virtual tours also allow for interpretative overlays like text panels, drawings, and new and historic photographs.

Laser scanning and photogrammetry aid the process of documentation significantly, but the data they produce can be difficult to interpret, requiring specialized skill and software, and the files costly to maintain. HABS/HAER/HALS drawings, on the other hand, are not only easy to use and interpret but can also be stored without threat to their future viability. Furthermore, the programs still rely on large-format, mostly black-and-white photographs that capture minute detail with amazing clarity, and the negatives are not subject to the degradation that plagues digital files.

The HABS/HAER/HALS programs will continue to embrace new recording technologies to meet increasing demands for accuracy, scholarship, and accessibility. We are particularly focused on the storage and preservation of born-digital products and currently maintain a large cache of field data in various iterations used for measured drawings, models, and virtual tours that we hope to be able to share with the general public as part of the formal documentation.

One of the HABS architects working with a laser scanner at Dry Tortugas National Park. | Credit: National Park Service

Photography is one area that will likely see significant changes in the near future as we work with the Library of Congress to develop standards for born-digital photographs that reflect the evolution of digital photography to meet the Secretary of the Interior’s Standards for Architectural and Engineering Documentation. The Library will be responsible for curating the digital archival record, much as it currently meticulously preserves physical negatives. The Library’s website already provides easy, copyright-free access to the materials, which can be downloaded at various resolutions depending on user needs. Hopefully, the collection can be fully indexed in the future to aid researchers looking for specific information.

Together with carefully researched historical reports, the HABS/HAER/HALS drawings and photographs serve as the basis for maintenance, rehabilitation, and interpretation. The documentation provides information that is valuable not only to preservation professionals but also to the general public—K–12 students and educators constitute one of its fastest-growing user groups.

Finally, we hope that SHPOs—as well as other producers and collectors of documentation—will continue to recognize the value of an online repository for information on historic sites and structures and will add to the HABS/HAER/HALS collection. While HABS/HAER/HALS has already made it easier to contribute by accepting smaller drawings sets, sketch plans, short-format historical reports, and the limited use of digital photographs as figures pages, some SHPOs produce documentation to program standards but still maintain it in their own archives or state repositories. Regardless of the methodology used to create documentation, a public archive of records on a wide range of historic sites is vital for preserving America's diverse heritage.

In the long term, the sky is the limit for employing these technologies to enhance our framework for cultural resource decisionmaking.

Richard O' Connor Ph.D., is the chief of Heritage Documentation Programs at the National Park Service.

Catherine Lavoie is the chief of the Historic American Buildings Survey at the National Park Service.