This cultural resource indicator is an index of sites on the National Register of Historic Places surrounded by limited urban development. It identifies significant historic places that remain connected to their context in the natural world.
Reason for Selection
Low-urban historic landscapes indicate significant cultural landscapes whose cultural context has been less impacted by urban growth. Cultural landscapes are “properties [that] represent the combined works of nature and of man” (UNESCO 2012). Reductions in natural habitat within these cultural landscapes reduce their overall historic and cultural value.
Input Data
The National Register of Historic Places reflects what Americans value in their historic built environment. It is the collection of our human imprint on the landscape that records through time our changing relationship with the landscape, bridging between modern life and our history by providing, as closely as possible, experiences that evoke our empathy and understanding of previous eras.
– The National Register of Historic Places (“NationalRegisterOfHistoricPlaces_South” point layer, used only in Georgia and Alabama, where no state-level dataset was available)
Some states maintain their own, improved versions of the National Register of Historic Places, while other states rely on the nationwide version maintained by the National Park Service. In Virginia, North Carolina, Florida, and South Carolina, we obtained the following state-specific point and polygon data for places on the National Register:
– Virginia listed historic districts boundaries
– Virginia listed site points
– North Carolina local district boundaries
– North Carolina NCHPO_NR_SL_DOE_Boundaries
– North Carolina NCHPO points
– Florida national register
– South Carolina NRHP_Districts-Areas_Non-Restricted
– SC_NRHP_Structures_points Non-Restricted
– 2016 National Land Cover Database (NLCD): Used to define urban areas as described in mapping steps
Mapping Steps
1) Urban areas were defined using the following classes from the 2016 NLCD - Developed, High Intensity; Developed, Medium Intensity; Developed, Low Intensity; Developed, Open Space. All urban pixels were classified as 1 and all other pixels were classified as 0.
2) The percent urban in a 270 m radius circle was calculated for each pixel using “focal statistics” in ArcGIS. Since the NLCD data resolution is 30 m pixels, we used 270 m (9 pixels) to approximate a 250 m radius. All pixels that were < 50% urban within a 270 m radius were retained.
3) We created a historic places layer as follows:
a. The North Carolina NCHPO points file contained points for both state level and national level historic places. To make these data comparable with data from other states, we removed the state-specific points using information from the attribute table (any point that had a blank value for the YearNR field was removed).
b. The state specific point layers (NC, SC, and VA) and the National Park Service-maintained “NationalRegisterOfHistoricPlaces_South” point layer (AL and GA) were merged together and buffered by 100 meters.
c. All polygon data and buffered point data were merged into one layer and converted to a raster with a 30 m cell size.
4) The historic places raster was then used to remove areas that fall outside of the historic places.
Final indicator values
Indicator values were assigned as follows:
0 = Not in the National Register of Historic Places (low)
1 = Historic place with nearby high-urban buffer
2 = Historic place with nearby low-urban buffer (high)
Known Issues
– There are spatial mapping errors for some of the historic areas.
– Some historic areas with cultural importance are not necessarily captured in the National Register of Historic Places.
– The approach to measuring urban growth doesn’t capture degradation to historic places that were historically in larger cities (e.g., courthouses and other downtown buildings). It also doesn’t distinguish between historic places that have always been urban and historic places that used to be low-urban.
–This layer underrepresents some historic areas in Georgia and Alabama because we only used the point National Register of Historic Places maintained by the National Park Service. We omitted the polygon layers because they contain many GIS errors and often overestimate the extent of historic sites.
Disclaimer: Comparing with Older Indicator Versions
There are numerous problems with using South Atlantic indicators for change analysis. Please consult Blueprint staff if you would like to do this (email hilary_morris@fws.gov).
Literature Cited
Homer, Collin G., Dewitz, Jon A., Jin, Suming, Xian, George, Costello, C., Danielson, Patrick, Gass, L., Funk, M., Wickham, J., Stehman, S., Auch, Roger F., Riitters, K. H., Conterminous United States land cover change patterns 2001–2016 from the 2016 National Land Cover Database: ISPRS Journal of Photogrammetry and Remote Sensing, v. 162, p. 184–199, at https://doi.org/10.1016/j.isprsjprs.2020.02.019.
Stutts M. 2014. National Register of Historic Places. National Register properties are located throughout the United States and their associated territories around the globe.
UNESCO (2012) Operational Guidelines for the Implementation of the World Heritage Convention [1]. UNESCO World Heritage Centre. Paris. Page 14.
