Illinois State Library

Illinois Digital Raster Graphics on CD-ROM

The Illinois State Library purchased the entire state set of Illinois Digital Raster Graphics (DRG's) from the United States Geological Survey (USGS) on CD-ROM. The 15 CD-ROMs contain all the 1:24,000, 1:100,000, and 1:250,000 topographic quadrangle maps covering Illinois in 1,138 files. The 1,138 files are in file number order on the 15 CD-ROMs, not alphabetically by the name of the quad or by the 5 digit block number from the topographic map index.

The Map Department staff at the Illinois State Library has created an alphabetical index from the quad name to the file number and 5 digit block number for each of the three scale series. The call number for these CD-ROMs is: SOFTWARE I 19.128:IL 6/File (nos.). You need the file number to get to the right CD-ROM and the 5 digit block number to get to the right data on the CD-ROM.

Please be aware that the digital version is not more recent than the published paper topo quad. In fact, since the Illinois State Library is not purchasing the revised Digital Raster Graphics, the Digital Raster Graphic may be older than a newly revised quad.

DRG 1:24,000 Index PDF         DRG 1:100,000 IndexPDF         DRG 1:250,000 IndexPDF

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