Maine GIS User Group


Analog GIS in the Digital GIS Age: A Municipal Archive and its Interconnection with the Modern Digital GIS Mapping of a 389-Year-Old City (Virtual Lunch & Learn)

  • 13 Apr 2021
  • 12:00 PM - 1:00 PM
  • Virtual

Video now available on our YouTube Channel

Guest Speaker: Dr. George S. Carhart, Engineering Archivist, Department of Public Works, City of Portland


Presenter abstract: GIS, Geographic Information Systems are not new, all that is new is the format in which it is presented and stored. Today we map and present geographic data in a digital/pixel format drawing on information stored in digital files. We layer information to build a map of a region or city. The layers can be turned on and off at the whim of the user to add and subtract meta data as needed. Within the layers hyperlinks can be made to text and image files which expand and elucidate the information being portrayed on the screen. Today if we were to design and build a city from the ground up all of this data would be in a digital format of some kind, that if properly developed would be easily and quickly integrated to present an interactive digital map/image of the city. However, this situation is at best extremely rare, most cities have a nondigital documental history. The Department of Public Works, Engineering Archive, in the city of Portland, Maine, holds some 100,000 plan sheets, thousands of site and report files, and thousands of survey and sewer field books, dating back to the early 19th century. Indeed, there are records in the City holdings, such as street acceptance documents and property deeds, that date back to before the beginning of 18th century. Though some of these have been digitally captured, much of it is still only in hard copy – paper format. The topic of our presentation today will be to show how the city of Portland is integrating its analogue Engineering Archive “GIS” into its modern digital GIS mapping. We will discuss how the integration of these materials into Portland’s GIS city map is in fact a two-way system, where the archive helps to build the map, and the map is used as a finding aide to identify items that are in the collection that are needed by the users of the GIS, be it in the office or in the field. 

Presenter bio: Dr. George S. Carhart has worked for the City of Portland since 2017. He has a Ph.D in History of Cartography from Universität Passau, Germany, and has previously worked at the Osher Map Library, Dresden University of Technology Institute for Cartography, and Trinity College, Dublin. 



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