digital reconstructions for collective historical memory

Some time I was questioning why do we/I need to know history, the history of family, nation, humanity. Why we always look back? And once I found - people, indeed society, has such thing as collective historical memory, that is built in our heads from our experiences as a group by sharing and it talks us about our culture and identity. The concept is quite clearly explained in wikipedia (Collective memory), as well as there is a free document from Wesleyan University in Middletown, Connecticut to read (Study of historical memory).

We do not notice that most of the historical memory we have is a collective, it's a shared memory - not collected empirically. What is interesting that with growing society people are searching for more and more earlier and broader historical memory. We can see that even from mass-media production, which from being interested in fantastic movies some decades ago are now presenting the documentaries, probably that is what the society is asking for - the collective history to share. And it is not just the trend of media information, I feel it is the trend in geographical information. For the places, spaces with great amount of geographical information that is well represented (mainly visualized), the historical geographical information demand is raised more and more often. It's all about the curiosity and about the desire of collective historical memory.

The historical geographical information representation is a part of reconstruction process, it's a spatial reconstruction process. Not long time ago, there was a movie made by Deutsche Welle about the reconstruction of the Berlin wall - I wrote about in the previous post. Now, the new project is published and presented for the society - the Early Washington Visualization done by Image Research Center (IRC).
The project can be found and is fully described on http://visualizingdc.com/



But let's have a look at the geographical/cartographical side of this project.


There are mainly two collaborators:
Peter G. Chirico, Geographer, U.S. Geological Survey
Donald A. Hawkins, Historical Cartographer
and one IRC specialist:
Lindsay Schroader, a Geographic Information System (GIS) specialist

Great project geographical aspect explanation in short:

Crucial elevation information was collected by P Chirico to create a database and build the historical elevation model representing 1888 topography, by digitizing elevation contours, spot
heights, and bathymetry data from four different sources.
The primary topographic contour data were manually digitized from 57 map sheets (1 sq. mile coverage) of the 1:4800-scale topographic map series by the U.S. Coast and Geodetic Survey (1888). This data provided an accurate reference for the 1790 elevation of the city, because most of the land had not been affected by building activities. 
Another map Hawkins’ 1791 Washington DC was drawn from Thomas Freeman and Nicholas King’s 1797 “Surface Profile Maps.”.
Within the vaults of the Library of Congress are plats that show the location of streams, roads, fences, ferries, some land use, and the location, dimensions, and construction materials of most major buildings in 1790. 
Later Chirico's 1888 contour lines and a georeferenced map from 1896 was used to georeference Hawkins’s 1791 topography map and 1791 digitized contour lines to produce a one shapefile.
The water line was the last section of contour lines to be edited. Along much of the coast there were wharfs that did not exist in 1790 and thus had to be removed, which involved not just removing the effects above the water, but also the impact a wharf has below the surface.

Dan Bailey and Lindsay Schroader Visualizing Early Washington DC, UMBC Imaging Research Center, Baltimore Maryland, USA (pdf).