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Digital Maps: Charting a Course in Libraries

Digital Maps: Charting a Course in Libraries. John A. Mess February 17, 2004. What is a Digital Map?. Map that has a digitized image Scanned map images Map that has digital coordinates Star charts, latitude/longitude coordinates Map that has vector defined features

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Digital Maps: Charting a Course in Libraries

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  1. Digital Maps: Charting a Course in Libraries John A. Mess February 17, 2004

  2. What is a Digital Map? • Map that has a digitized image • Scanned map images • Map that has digital coordinates • Star charts, latitude/longitude coordinates • Map that has vector defined features • Topographic maps • Map that is generated heuristically • Political and demographic maps

  3. GIS – Geographic Information Systems • Like any system, the more closely you look the less predictable it becomes. • GIS development focuses on the level of specificity needed. • For most applications, vector-based maps are used because • They can be dynamically modified • They are more compact • They can be used at multiple resolutions without loss of detail

  4. Digital Map Formats • Vector-Based Formats • FITS – Standard for Government • ARC – GIS format very common • VRML – 3D Modeling format • Raster-Based Formats • DejaVu – Image Wavelet Compression • JPEG, GIF, TIFF, etc. – Image Pixelation

  5. Digital Orthoquads • Are vector-based files (“data programs”) not images • Require software to translate the “data program” instructions • Examples: TIGER dataset, Digital Orthoquads

  6. Digitized Map Collections • Printed maps are scanned and made into raster image files. • TIFF – lossless image format [1/1] • The image can be reduced in size by using compression schemes • GIF – lossless compression [1/20] • JPEG – lossy, heuristic compression [1/50] • DejaVu – lossy, wavelet compression [1/200]

  7. Reno’s Digitized Maps

  8. Searching the Collection – Predefined Searches Categories

  9. View All Maps

  10. Advanced Searching

  11. UNLV’s Digitized Map Project A Project History A Project History • UNR puts up historical maps on its ContentDM server • UNR staff are invited to UNLV to discuss their projects and identify complementary collections • Historical maps are identified by Special Collections • Systems helps obtain the DejaVu encoding software • WDS (Annie Sattler) begins the scanning and conversion of the roughly 50 maps from TIFF into JPEG and DejaVu formats • BMS (Kathy Rankin) creates metadata records for the maps Next Steps • Create web frontpiece for the digitized collection • Create customized searches that highlight the digitized map collection • Announce the collection • Assess use by the community for future development Next Steps

  12. Choosing the Maps • Peter Michel working with UNR’s Linda Newman to identify maps that would be of historical interest • UNLV Maps highlight • Chronology and history of Western Cartography • Incorporate visually interesting and historic maps • UNR Maps highlight • Topographic and geological features • Mining and historic maps of Northern Nevada

  13. Digitizing the Maps • Resolution: • 300 DPI • Format: • TIFF, JPEG, DejaVU • Time required to Convert: 30-45 min per map • Scanning: 20-25 min • Convert TIFF to JPEG: • 5-10 min • Convert TIFF to DejaVu • 5-10 min

  14. Selection of DejaVu • Created by Lizard Tech • Used by the Library of Congress • Free version available for use • Achieves small file size with wavelet compression • Allows for zooming while retaining feature definition

  15. Map Examples Approximate Sizes: • TIFF Size: 120.0 MB (1/1) • JPEG Size: 8.5 MB (1/15) • DejaVu Size: 0.65 MB (1/200)

  16. g_4300_1864_j64_front TIFF 126 MB JPEG 6.8 MB

  17. Using the DejaVu Plugin

  18. Comparison of DejaVu and JPEG

  19. UNLV’s Digitized Map Project –Next Steps • Continue to identify maps and materials of interest to researchers • Provide links into the catalog to allow others searching to find maps more readily • Mount digitized maps on the ContentDM server to make it possible for other institutions to harvest the metadata

  20. Other university libraries have begun working with Geography, Geology, and Political Science Departments to create Map Centers Providing support and consulting for graduate students and outside users with the Center in proximity to printed map collections Many researchers use or need to create maps: Anthropology, Archeology, Sociology Political Science Marketing, Business, Economics Geology, Geography, History Forensics, Urban Studies, etc. Other Digital Map Programs

  21. Future of GIS Systems and the Impact on Libraries • Libraries continue to be a principal source for government maps but these require special software • Older maps provide valuable information for researchers and benefit from digitization for access and preservation • The presence of MapQuest and other online mapping services is altering the nature of user interactions and information needs • The ability of web browsers to manage more formats has pushed the possibilities of 3D maps.

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