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| Courtesy North Carolina Maps Project |
Archives and libraries are making the leap from digitized
maps to digital maps. What’s the difference? The former is a scanned document while the latter makes it possible for users to
interact, compare, and add their own data to digitized historic maps in ways that would never have been possible using
only the paper originals.
If you have research to do in North Carolina, you’ll be
interested to hear about the North
Carolina Maps Project, a newly completed map digitization project involving the
North Carolina State Archives, the University of North Carolina at Chapel Hill,
and the Outer Banks History Center.
The three-year collaborative project was funded by a grant
from IMLS to digitize and share online images of historic maps from these three
partner collections. More than 3,300 different maps, dating from 1584 to 2000,
are included.
Maps are difficult records to preserve and provide access to
because they are fragile yet bulky. The digitized collection provides free and
streamlined access to materials, and it unifies the complementary holdings of
the three partners.
“Users have responded enthusiastically from the outset,
often writing to thank us for making the materials available online (and
frequently asking for more),” says Nicholas Graham of North Carolina Digital
Heritage Center.
In an article in March/April 2011 issue of Archival Outlook, a
publication of the Society of American Archivists, Graham writes:
Moving from Digitized to Digital Maps Geographic Information
Services (GIS) applications are nothing new to professionals in geography or city
planning. Most large college and university libraries have had GIS tools and
labs available for years. However, GIS work was primarily performed by
specialists until the release of Google Maps and, especially, Google Earth.
These free, user-friendly applications make it easier for users to manipulate
and interact with digital maps, geographic information layers, and satellite
images. In order to move from digitized maps to digital maps in the North
Carolina Maps Project, a couple steps were necessary.
First, we had to georeference selected historic maps and
devise ways to present them online. Georeferencing is a familiar process for
GIS specialists. It involves assigning a digital image and assigning it a place
in physical space. For our project, this usually involved comparing a historic
map to existing, known geographic information, such as a layer of streets or a
satellite image. The person conducting the georeferencing finds a spot on the
historic map that matches a corresponding spot in the known geographic layer,
such as a road or railroad intersection. The software then aligns the historic
map to the existing digital information. The more points found on the historic
map, the more accurate the results.
Of the more than 3,000 maps available on the North Carolina
Maps Project website, about 200 are presented as georeferenced, or “historic
overlay,” maps. There’s no easy or automatic way to georeference a map. It can
take many hours to complete even one. Once a historic map is georeferenced, it
can be used like any other geographic layer.
What the georeferencing means for users of the new North
Carolina Maps Project is the ability to view a historic map directly on top of
a current map or satellite photo, generating a comparison of the same area past
and present. Changing roads and borders, seeing the location of specific
buildings, another command are possible.
Graham also said, “Archivists are finding that users want to
do more than just look at images of old maps; they want to interact with them,
too.” And those users sound like genealogists!
To access the North Carolina
Maps Project, click here.
Similar projects combining user-friendly GIS
applications offered by Google with collections at the University of
Connecticut and Ball State University are underway.
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Looking forward to my presentation Saturday at the Computer Genealogy Society of San Diego on managing your digital research environment. Hope to see some readers there.
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. 2nd ed. Baltimore: Genealogical Pub. Co., 2006. 
. Washington: Library of Congress, 1998. 
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