Winter  >>  2012  

Historic Preservation

Bridging the Gap Between GIS Experts and Field Researchers

Fig. 1

Stone Mountain is one of the world’s largest exposed granite domes, located in Stone Mountain, Georgia, approximately fifteen miles east of downtown Atlanta. It is well-known for its geology, as well as the large bas-relief sculpture depicting Jefferson Davis, Robert E. Lee, and Thomas “Stonewall” Jackson, Confederate leaders of the Civil War. Image courtesy of Northrop Grumman.

Fig. 2

Snapshot of a GeoPDF created to support the project design process for a new highway that crosses an archaeologically sensitive area. Layers that can be turned on and off include multiple versions of the project alignment, known and potential archaeological resources, and sources of disturbance such as a rapidly migrating stream channel.

Fig. 3

Snapshots from a GeoPDF created to support the identification of historic buildings and potential archaeological features. The four clips show historic Sanborn Insurance Company maps for a single block for a period covering roughly 60 years.

Fig. 4

This 1886 Sanborn Insurance Map, when overlaid on a current aerial photo, provides architects/historians with an important tool for determining the age of existing buildings. It also provides archaeologists with information on the potential location of building remains and buried features such as cisterns and privies.

is Chief Technology Officer at TerraGo Technologies. Demmy is one of the patent holders for the process that creates georeferenced PDF files. He holds a BA in Physics from Florida State University and an ME and Ph.D. in Agricultural Engineering from the University of Florida. He comes by his interest in historic preservation naturally; his father and namesake is the former director of historic preservation for Pensacola, Florida.

Our nation is fortunate to encompass a treasure trove of sites and landscapes that shed light upon the history of America. However, while these sites and landscapes are a rich, celebrated part of America’s evolution, they require proper preservation planning services to maintain the historical integrity and, in many cases, the aesthetic beauty. Many of these sites need cultural resources studies, such as analyses of cultural landscapes, archaeological and architectural surveys, evaluation and mitigation to ensure that they will provide lasting value for many generations to come.

Gray & Pape, Inc. provides these types of services to plan mitigation activities and related expenditures for archaeological and architectural resources for some of the nation’s most storied sites. The firm’s highly specialized analysts and researchers expertly identify archaeological and architectural resources for a wide range of projects. In addition, the firm caters to a diverse set of clients, including consultants and project managers, as well as public relations, land planning, engineering and construction professionals.

From Paper to Digital

A typical project for Gray & Pape includes the firm’s in-house GIS experts, the client GIS resources and the archaeologists and historic architects who analyze sites and collect information in the field. The latter subject matter experts often have little or no direct experience with GIS. The firm’s projects have in the past relied on a paper-based field data collection process.

Maps used in the field were printed from the GIS and delivered to the experts in the field. These paper maps were then annotated with notes and sketches based on observations in the field. After markup, the maps were returned to the GIS technician who then translated the hand-written notes and drawings into entries in the GIS, which were subsequently analyzed. Unsurprisingly, field subject matter experts often did not use GIS tools directly to analyze the data or view historical maps and images.

Gray & Pape’s GIS team saw the need and the opportunity to create a bridge between these workflows to enable seamless and easy digital sharing of GIS data and field observations between the GIS experts and the archaeologists and architectural historians conducting research. Gray & Pape tapped TerraGo Technologies for its geospatial collaboration expertise and software to allow their clients the ability to extend the access and application of their geospatial assets by creating highly portable and interactive GeoPDF maps and images out of complex GIS data. With TerraGo GeoPDF maps and imagery, users can more effectively capture intelligence from the field and ‘roundtrip’ the data back to the enterprise GIS.

Working with GeoPDF maps and imagery is simple and highly intuitive, offering vast improvements over paper-based processes. Users open GeoPDF files with Adobe Reader, as they would any PDF. However, GeoPDF maps provide views to map layers and feature attributes, which heretofore were typically limited only to GIS. Moreover, with TerraGo Toolbar, an Adobe Reader extension, users can add GeoMarks – georeferenced markups – to which notes, photos, and a variety of other media can be attached.

To bridge the gap between the back office and the field, Gray & Pape implemented a TerraGo solution that included using TerraGo Publisher for ArcGIS to create custom GeoPDF maps and imagery, replacing the paper maps of the more typical workflow. The firm also used TerraGo Composer to assemble GeoPDF maps and reports into desired configurations. And, finally, the free TerraGo Toolbar enabled mobile researchers to record field data on the GeoPDF maps and export shapefiles with notes and markings to be integrated back into the GIS environment without the tedious and error-prone manual translation of the hand-written markups by the GIS analyst.

Historic Preservation During Infrastructure Planning

On a recent project that involved identifying historically significant structures to assist in future infrastructure planning, Gray & Pape field experts conducted ‘windshield’ surveys while traveling to many sites to observe and map locations of hundreds of historical buildings. See examples in Figures 1-2. Each area of interest was identified using aerial and topographic maps that were converted to portable GeoPDF maps, which are easily opened in Adobe Reader in the field. After making referenced notations and marking sites on the GeoPDF maps, completed maps and field notes were sent back to Gray & Pape’s GIS expert to import the data into ArcGIS. (For more information about mobile solutions, see Sidebar 1.)

Gray & Pape noted that with a GPS device, mobile researchers would be provided only their current location, but often the point of interest was some distance away. The ability to place a GeoMark anywhere on the map enabled the creation of rich observations, which included digitized sketches of features of interest. Within GeoPDF maps, users with the free TerraGo Toolbar can dynamically view latitude and longitude as the mouse cursor moves across the map, measure distances, make notes, draw shapes, attach images, and export these data for ArcGIS or other GIS systems with just a few clicks.

Another Gray & Pape project required layering historical maps over a project area map to help identify parcels or structures that have not changed for 150 years. This provided rich, dynamic GIS-like data presented in layers and easily studied by experts and non-experts alike to see how site snapshots evolve over time in a geospatial context. See examples in Figures 3-4.

Using TerraGo software and GeoPDF files, Gray & Pape was able to implement an all-digital collaboration workflow. The firm condensed and simplified fairly complex GIS technology and got it out to the people in the field in a simple and straightforward package they could use.

For one project, Gray & Pape distributed more than 80 pages of GeoPDF maps, collected markups, and imported back into ArcGIS for a complete roundtrip of data. The maps showed aerial imagery and USGS topographic data. Field experts used TerraGo Toolbar to place a GeoMark for each historical building, cross-referencing field notes to a unique number assigned to each. The completed maps and field observations were electronically transmitted back to a GIS expert, who imported the GeoMarks into ArcGIS. This method of field verification eliminated manual transfer of data to ArcGIS, which saved time and improved accuracy.

In one major project over the last year, the firm had to create a planning tool for the evaluation of archaeological sensitivity across a large study area. Its investigators and a series of other consultants were tasked with evaluating multiple potential project routes within this area. There was a great deal of variability in GIS resources available to the various consultants – some were entirely without access to or expertise with GIS.

As such, Gray & Pape created a single GeoPDF product with the many layers of information affecting sensitivity, and distributed it across the project team. By simply creating a new copy of the GeoPDF map for each map revision, the firm could be certain that all parties were looking at the identical data.

In addition to supporting field data collection, TerraGo software has made sharing survey results easy. Gray & Pape can produce user-friendly GeoPDF map reports that enable a client to turn on and off multiple map layers and evaluate a project’s cultural resources without using GIS software. All project participants can receive a robust GeoPDF map report on CD bundled with other deliverables. (TerraGo has the capability to deliver ‘on the cloud’ via its partnership with GeoEye. See Sidebar 2.)

The right GIS solutions can help organizations like Gray & Pape to achieve a higher level of effectiveness and efficiency, and, in the specific case of Gray & Pape, ultimately to preserve and protect the treasures of our past.

Submit the first comment

Comments [ 0 ]

Sensors & Systems | Monitoring, Analyzing and Adapting to Global Change | Stay in tune with the transformation. Subscribe to the free weekly newsletter.