IFLA Section of Geography and Map Libraries

	IFLA Section of Geography and Map Libraries
If you have any suggestions, comments or items that you would like to see added to this collection, please direct your messages to: libmap1@uconnvm.uconn.edu

Title

Digital Map Librarianship: Using the Paper Collection

Intro
Locating and retrieving appropriate electronic data can be difficult. In the United States the government is required by law to distribute information obtained or created with public funds. In addition, the US Government cannot hold copyright on the information it produces... the data is freely distributable. While data from the federal government is fairly extensive, data from lower levels of government, ie, states, counties and localities, is not governed by the same laws and can be more difficult to obtain. Likewise, some data may just not be available electronically. There are several ways, however, to move geo-spatial data from analog to digital, primarily scanning and digitizing.

Scanning
The process of scanning results in a picture of the map or document. The scan is a raster image of the paper original. Although scanners for regular sized, black and white paper documents are relatively inexpensive, scanners that accomodate maps will necessarily be large, capable of color and more expensive. Scanners come in several varieties, drum, pull-through and flat bed. Drum scanners require the map to be afixed to a revolving surface and are therefore not practical for very large or fragile maps. Pull-through scanners accomodate almost any length of map, and are wide enough to accomodate all but the very largest maps. As the name implies, these scanners have rollers that pull the map through the light mechanism. Generally the rollers are gentle, but very fragile maps are probably still not good candidates for pull-throughs. Flat bed scanners look like very large photocopiers. The map is placed on the window and the scanner moves underneath the glass. This is probably the best solution for fragile maps, but the size of the scan is limited to the size of the bed. Because scanners are very expensive, the library may choose to have the scanning perfomed by a company specializing in digital conversion. Be careful to select a company that can handle special formats, such as maps. Scanning caputures all the information on a map in one process. The scanner will however, pick up every flaw or blemish on the map as well. Also, using the raster image in a vector GIS program, such as ArcInfo, may require extra programming and conversions. For additional information on scanning for historic preservation see the Library of Congress, Geography and Map Division’s panoramic map project, or a project at Columbia University to compare different scanning, storage and compression techniques.

Digitizing
Another means of creating electronic information from the paper map is digitizing. Digitizing will result in a vector file that is more compatible with programs like ArcInfo. In this process the map is placed on a special sensitive table and the lines on the map are traced using a device called a digitizer cursor or puck. Bascially the operator manually traces and labels all the lines and points on the map into the computer. Depending upon the complexity of the map, digitizing can be a very tedious and time consuming process. For accuracy, the person doing the digitizing must be very careful. With an experienced digitizer, good equipment and enought time, the result can be some excellent data.
The conversion of analog to digital data can be a time consuming and expensive process. Supply digitizing equipment, scanners and the accompanying staff support are probably beyond the means of most libraries. Librarians would be wise to explore all avenues for finding data already digitized before expending resources on digitizing or scanning.

Suggested Citation
Lamont, Melissa, "Digital Map Librarianship: Library Functions; Using the paper collection; Scanning and Digitzing." Digital Map Librarianship: a working syllabus, 63rd IFLA Conference, Copenhagen, Denmark. (4, Sept. 1997) <http://magic.lib.uconn.edu/ifla/lb_out.htm>

Melissa Lamont
Data Library and Archives
Woods Hole Oceanographic Institution
McLean Lab. MS#8
Woods Hole, MA 02543
mlamont@whoi.edu

Title	Digital Map Librarianship: Using the Paper Collection
Intro	Locating and retrieving appropriate electronic data can be difficult. In the United States the government is required by law to distribute information obtained or created with public funds. In addition, the US Government cannot hold copyright on the information it produces... the data is freely distributable. While data from the federal government is fairly extensive, data from lower levels of government, ie, states, counties and localities, is not governed by the same laws and can be more difficult to obtain. Likewise, some data may just not be available electronically. There are several ways, however, to move geo-spatial data from analog to digital, primarily scanning and digitizing.
Scanning	The process of scanning results in a picture of the map or document. The scan is a raster image of the paper original. Although scanners for regular sized, black and white paper documents are relatively inexpensive, scanners that accomodate maps will necessarily be large, capable of color and more expensive. Scanners come in several varieties, drum, pull-through and flat bed. Drum scanners require the map to be afixed to a revolving surface and are therefore not practical for very large or fragile maps. Pull-through scanners accomodate almost any length of map, and are wide enough to accomodate all but the very largest maps. As the name implies, these scanners have rollers that pull the map through the light mechanism. Generally the rollers are gentle, but very fragile maps are probably still not good candidates for pull-throughs. Flat bed scanners look like very large photocopiers. The map is placed on the window and the scanner moves underneath the glass. This is probably the best solution for fragile maps, but the size of the scan is limited to the size of the bed. Because scanners are very expensive, the library may choose to have the scanning perfomed by a company specializing in digital conversion. Be careful to select a company that can handle special formats, such as maps. Scanning caputures all the information on a map in one process. The scanner will however, pick up every flaw or blemish on the map as well. Also, using the raster image in a vector GIS program, such as ArcInfo, may require extra programming and conversions. For additional information on scanning for historic preservation see the Library of Congress, Geography and Map Division’s panoramic map project, or a project at Columbia University to compare different scanning, storage and compression techniques.
Digitizing	Another means of creating electronic information from the paper map is digitizing. Digitizing will result in a vector file that is more compatible with programs like ArcInfo. In this process the map is placed on a special sensitive table and the lines on the map are traced using a device called a digitizer cursor or puck. Bascially the operator manually traces and labels all the lines and points on the map into the computer. Depending upon the complexity of the map, digitizing can be a very tedious and time consuming process. For accuracy, the person doing the digitizing must be very careful. With an experienced digitizer, good equipment and enought time, the result can be some excellent data. The conversion of analog to digital data can be a time consuming and expensive process. Supply digitizing equipment, scanners and the accompanying staff support are probably beyond the means of most libraries. Librarians would be wise to explore all avenues for finding data already digitized before expending resources on digitizing or scanning.
Suggested Citation	Lamont, Melissa, "Digital Map Librarianship: Library Functions; Using the paper collection; Scanning and Digitzing." Digital Map Librarianship: a working syllabus, 63rd IFLA Conference, Copenhagen, Denmark. (4, Sept. 1997) <http://magic.lib.uconn.edu/ifla/lb_out.htm>