The Temporal Geocoder will enable historians, librarians, archivists, scholars and the public to assign geographic locations to historical materials housed in libraries, archives and museums, enabling broader access and location-based searching.
Philadelphia, PA, April 2, 2013 – Azavea, an award-winning geospatial data analysis software company, was awarded a $150,000 Phase I Small Business Innovation Research (SBIR) grant from the National Science Foundation to create a web-based historical mapping system that will enable geographic indexing of historical documents. The software is aimed at supporting a wide range of government, commercial, academic and other research projects involving the analysis of geographic data through time, with particular emphasis on projects related to public health, epidemiology, political science, history, and genealogy.
Search engines, like Google and Bing, are successfully indexing and making available enormous amounts of contemporary human knowledge and activity. However, much of human experience is not contemporary; it is “old knowledge” that is housed in the world’s libraries, archives and museums, and most of this material has yet to be digitized and indexed. Many of these documents have addresses and place names, but they can neither be searched geographically nor placed on maps because the location references are based on old street names and place names.
With modern web maps, the act of turning an address into a map location is now easier than ever. But digital mapping systems focus on the contemporary world and a time-enabled geocoder has yet to be developed. Address numbers, street names, and place names are dynamic and change a great deal over time. This is particularly true in urban locations, where streets are frequently added, changed, moved or vacated from the urban landscape to reflect redevelopment, migration, updates to land use regulations, annexation, growth or decline of individual neighborhoods, and compliance with the E911 emergency system. As a consequence, “1234 Green St” in 1856 may not be the same location as “1234 Green St” in 2013. These changes have been incrementally recorded in documents such as municipal ordinances, directories, and paper maps, but have not been consolidated into a single database, cannot be easily traced back and forth through time, and are not referenced in any contemporary mapping system. This poses a complex problem for researchers trying to determine a current location based upon an historical address and makes the automation of geographic indexing in historical documents all but impossible.
The new Temporal Geocoder project will address these challenges with two solutions. First, Azavea will create an online tool that will enable historians and the general public to collaboratively create a digital database of historical streets and neighborhoods. Second, they will implement a prototype software service that can geographically tag documents based on a combination of location and time. Together, these two components will provide the ability to find historical locations on a current map and facilitate research that relies on these historical knowledge repositories.
The idea for the Temporal Geocoder originally arose as Azavea worked with the Philadelphia City Archives to geographically tag thousands of historical photographs and maps for inclusion in the PhillyHistory.org website (www.phillyhistory.org). The company found that it was extremely difficult to accurately georeference the historical images to their contemporary locations on a map without a comprehensive index of street name changes. As a result, Azavea developed a database of street names, building on the work of a former employee of the Philadelphia City Archives, which can be found at www.phillyhistory.org/HistoricStreets/.
The development of the Temporal Geocoder is supported by the Small Business Innovation Research (SBIR) program of the National Science Foundation (Award No. IIP-1248753).