INTRODUCTION

The geologic map of the Wallace 1° x 2° quadrangle (Harrison and others, 1986) was originally digitized by staff at the Earth Resources Observation Systems (EROS) Data Center prior to 1994 and completed by U.S. Geological Survey staff and contractors at the Spokane Field Office (WA) in 2000 for input into a geographic information system (GIS). The resulting digital geologic map database can be queried in many ways to produce a variety of geologic maps. Digital base map data files (topography, roads, towns, rivers and lakes, etc.) are not included: they may be obtained from a variety of commercial and government sources. This database is not meant to be used or displayed at any scale larger than 1:250,000 (e.g., 1:100,000 or 1:24,000). The digital geologic map graphics and plot files (wal250k.gra/.hp) that are provided in the digital package are representations of the digital database. They are not designed to be cartographic products. The map area is located in north Idaho and western Montana (see Fig. 1 on map). This report describes the methods used to convert the geologic map data into a digital format, the ArcInfo GIS file structures and relationships, and explains how to download the digital files from the U.S. Geological Survey public access World Wide Web site on the Internet. We thank Karen S. Bolm (USGS) for her review of the manuscript and digital data.

 Description of files available to download

 File size

8 KB 

 I-1509-A in Portable Document Format (PDF)

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940 KB 

 Complete digital data package

Utilities to extract TAR and GZIP files on your Windows or Macintosh

8.8 MB 

16 KB 

 Map Files in HPGL2 format as a UNIX compressed (and, in some cases, TAR) file.

Map scale: 1:250,000

Page size: approximately 43" x 28"

3.1 MB