Message-Id: <199912171927.MAA21274@dns.ccit.arizona.edu> Date: Fri, 17 Dec 1999 14:38:27 -0500 From: Tamara Swora-Gober <mailto:tswo@LOC.GOV> Subject: LC National Digital Library Program announces release of Civil To: mailto:IMAGELIB@LISTSERV.ARIZONA.EDU
This message is being widely posted.****************************************** The Library of Congress National Digital Library Program and the Geography and Map Division announce the release of “Civil War Maps” at:
http://memory.loc.gov/ammem/gmdhtml/cwmhtml
This collection documents battles, troop movements, reconnaissance efforts and locations of fortifications and contains approximately 2240 Civil War maps and charts and 76 atlases and sketchbooks that are held within the Librarys Geography and Map Division. A selection of these maps, based on the publication, “Civil War Maps: An Annotated List of Maps and Atlases in the Library of Congress”compiled by Richard W. Stephenson, will be made available through American Memory. Updates will be made to this collection on a monthly basis.
Though the large majority of these maps were created during the time of the Civil War, a number were created afterwards to illustrate or explain certain events or battles. Publishers in the North and South created maps included in this collection by both Union and Confederate forces. An introductory essay provides a discussion of mapping during the Civil War highlighting materials that are within the Geography and Map Division of the Library.
Of special interest are maps created by Major Jedediah Hotchkiss, a topographical engineer for the Confederate Army. Hotchkiss’s granddaughter donated these maps to the Library of Congress in 1948. Generals Lee and Jackson used a number of his maps as they planned strategy for various battles. Future updates will include images from his notebooks, which contain detailed notes about his various map projects. Also included are maps that were owned by General William Tecumseh Sherman. Some of these maps, which were donated by members of his family, document Sherman’s military campaigns in Tennessee, Mississippi, Georgia and the Carolinas. Users may also be interested in maps that were created as propaganda items to encourage support of one side or the other during wartime and maps that were published in various newspapers. Panoramic maps and city plans are included within the collection.
Digitizing the Collection The digital images were created by staff in the Geography and Map Division by scanning the original map on a large-format (24 x 34 inches) flatbed scanner using RGB (red- green-blue) color separation. Each raster image was produced by scanning the item at a resolution of 300 dots-per-inch and converting the resulting proprietary file format to TIFF format. These TIFF files, which average approximately 180Mb, are moved over a network to Surestore jukebox 1.3Gb magnetic optical platters for temporary offline storage.
Following scanning, the TIFF files were enhanced using the WindowsNT version of xRes, an image processing software, to rotate, crop, adjust brightness or contrast, and stitch together TIFF images for items requiring multiple scans. The TIFF files were compressed, using a wavelet-based image compressing software called Multi-Resolution Seamless Image Database, or MrSID, from Lizard Tech. This software integrates multiple resolutions of an image in a single file which enables Internet users to zoom in, getting more and more detail. Although MrSID is a "lossy" compressor, the images were compressed at a ratio of 22:1 without experiencing any loss of information. The final step was the creation of a small GIF file for use as the initial thumbnail display of the item. After completing the scanning, the Archive TIFF file along with the SID and GIF files are stored on the Librarys RS6000 World Wide Web server.
For questions please send email to mailto:maps@loc.gov.