-------- 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 The collection contains superseded US Geological Survey and US Army topographic maps, with dates ranging from 1891 to the 1960s.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 There are likely additional superseded topographic maps for North Carolina that are still not included in this collection.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]