The Yukon Digital Geology CD-ROMs present a variety of geoscience data sets in digital format on the geology of the Yukon Territory. They include syntheses of bedrock geology and glacial limits, compilations of geochronology, paleontology, mineral occurrences, oil and gas wells, and a compendium of aeromagnetic images. A subset of a public domain topographic data set (Digital Chart of the World, by ESRI, Inc.) is included for georeference purposes. For ease of use, data sets are divided geographically into 45 map tiles corresponding to the National Topographic System (NTS) 1:250,000 quadrangles. Data sets spanning the entire Yukon Territory are also included for use on sufficiently powerful computers and GIS software. Each theme for all of the 45 map tiles is presented in two projections. An Albers Equal Area projection, on disc 1, is provided to allow seamless integration of adjoining tiles throughout the Yukon. The complete data set is also provided on disc 2 in the UTM coordinate system, which is commonly used for accurately plotting data at the local scale (see Projections). Vector data files are also presented in several different file formats (ArcInfo coverages; Interchange (.e00), dBase (.dbf), shapefiles (.shp), and image data files are presented in band interleaved by line (.bil), and tagged image file format (*.tif) to allow easy importing of data into commercial GIS software. These CD-ROMs also include a limited edition of SurView, a viewing application for Microsoft Windows, developed at the Geological Survey of Canada and originally released as GSC Open File 2661. SurView runs directly off the CD-ROM. It can display, print, and query the *.shp and *.bil files. This provides an opportunity for those without specialized GIS software to delve into the realm of digital geoscience data and explore the Yukon Digital Geology databases on their own PC.