-------- Original Message --------
Subject:        Historical NC Topo Maps Online
Date:   Thu, 27 Sep 2007 17:09:07 -0400
From:   Jeff Essic <[log in to unmask]>
To:     Maps, Air Photo & Geospatial Systems Forum <[log in to unmask]>

The NCSU Libraries has compiled an extensive collection of historical
topographic map images of North Carolina that can be downloaded for
free from the Web site http://www.lib.ncsu.edu/gis/historictopos.html.

The collection contains superseded US Geological Survey and US Army
topographic maps, with dates ranging from 1891 to the 1960s.  Over
one-third of the maps were published prior to World War II and are
known as "15-minute maps" because they cover 15 minutes of latitude
and longitude.  Many of the printed originals are maintained in a
collection by the North Carolina Geological Survey (NCGS).  Others
were loaned by the UNC Maps Collection for scanning.

The digital collection is composed of both georeferenced JPEG 2000
format images and lossless (unaltered) non-georeferenced JPEG 2000
images.  JPEG 2000 is a relatively new, yet widely supported image
format that offers superior compression performance.

The georeferenced images may be used in GIS software to provide a
historical basemap when overlaid with other current spatial data to
identify changes in landscape features.  The lossless images, when
plotted, appear nearly identical to the original scanned map.

To find the map image you would like to view, you can scroll the list
online and pick from the mapsheet names.  Alternatively, you can use
the index shapefiles or Google Earth KML index files to identify the
maps that cover your area of interest.

Senior Geologist Jeff Reid provided the maps and led digitization
efforts at NCGS.  As part of a partnership with Library of Congress
under the National Digital Information Infrastructure and Preservation
Program (NDIIPP), NCSU Libraries staff georeferenced the map images
and performed additional rectification, compression, file management,
and indexing steps prior to putting the digital maps online.

There are likely additional superseded topographic maps for North
Carolina that are still not included in this collection.  If you know
of maps that should be added, please contact Data Services Librarian
Jeff Essic at 515-5698 or [log in to unmask]