Glaciotectonic Map of North America

Digital Data

Digital data for the Glaciotectonic Map of North America (Aber et al. 1995) are available in a format that could be used with either ARC/INFO or ArcView software (see DASC). ARC/INFO is a vector-based geographic information system for capture, management, analysis, and plotting of georeferenced data. ArcView is a Windows-based means of accessing, displaying and manipulating ARC/INFO data bases.

The digital data base was created originally using ARC/INFO at the University of Regina, Saskatchewan, Canada. Data entry (digitizing) and preliminary file editing were done with ARC/INFO version 5; editing and plotting of the final map were carried out using version 8 at the Canadian Prairie Farm Rehabilitation Administration, also in Regina. Full details were described by Aber et al. (1993) regarding construction of the data base, contributors, and production of maps--jump to references.

The digital data are provided as ARC/INFO export files in single-precision format. The data base consists of these files:

TECTONIC.E00: glaciotectonic features; manually digitzied from 1:250,000 and 1:500,000 topographic maps (Aber et al. 1993).
GLACIAL.E00: limits of ice-sheet glaciations; manually digitized from Dyke and Prest (1986) and other sources.
GEOLOGY.E00 to E03: major geologic boundaries; manually digitized from Douglas (1969) and other sources.
GEOGRAPH.E00 to E05: basic geography; derived in digital format from World Data Bank II (U.S. Federal Computer Products Center); edited and corrected for topological errors.

Complete identification is given for each feature code in these files (see ID listing). The GEOGRAPH, GEOLOGY, AND GLACIAL files are provided as used for plotting the printed map (see glaciotectonic map). However, the TECTONIC file consists of glaciotectonic data at the resolutions that they were originally digitized. In other words, the glaciotectonic data are not generalized, as in the manner depicted on the printed map.

Data Archive

The Data Access and Support Center (see DASC) at the Kansas Geological Survey (USA) is the archive and distribution site for digital data of the Glaciotectonic Map of North America. Digital data are available via anonymous FTP at the following address:

ftp://ksgis.kgs.ukans.edu/gisdata/glac_tec/

In this directory are two files:

glac_tec.zip (compressed Arc-Info export files, about 22.5 Mb)
glac_tec.txt (ascii documentation file, about 7.5 Kb)

Directions to download and extract the digital data are given in the DASC Core Database Catalog. Note: each coverage is merged into a single file in the DASC archive.

Instructions for ArcView

These instructions assume that the user has some familiarity with ArcView. Begin by setting up a directory named NAGLATEC on your computer's hard drive. Under NAGLATEC set up a subdirectory named EXPORT. Place the TECTONIC, GEOLOGY, GLACIAL, and GEOGRAPH files into this subdirectory; also copy the ArcView IMPORT.EXE program into this subdirectory. The following example shows how to run the IMPORT.EXE program using simple DOS commands:

C:\> CD NAGLATEC\EXPORT

C:\NAGLATEC\EXPORT> IMPORT TECTONIC C:\NAGLATEC\TECTONIC

Repeat this procedure for the other export files. Note: do not enter export file extension names. You also should copy the project files (*.APR) into the NAGLATEC directory. When these procedures are completed, you should have the following directory structure:

C:\NAGLATEC>: EXPORT>; TECTONIC>; GEOLOGY>; GLACIAL>; GEOGRAPH>; glatec1.apr; glatec2.apr

In addition to data files, two project files are provided for use with ArcView (version 2.0b). These project files create map and legend displays of the data base. The project files are:

GLATEC1.APR, intended for "low-resolution" computer monitors.
GLATEC2.APR, intended for "high-resolution" computer monitors.

Each project file contains three views that depict various components of the data base:

View 1 is a simple display of all data without a separation of classes within each category.
View 2 is a detailed display of classes for the GEOLOGY and GLACIAL categories.
View 3 contains a detailed display of classes for the TECTONIC category.

You are now ready to display the map with ArcView. Choose the "open file" selection from the file menu; move to the NAGLATEC directory, and select GLATEC1 project file. If GLATEC1 fills only a small portion of the monitor screen, you may want to try GLATEC2. Given the variations in monitor resolutions and colors, these project files may produce somewhat different and unpredictable results with certain monitors. Of course, users who are knowlegdeable in ArcView can create new views and project files as appropriate.

Copyright Statement

Digital data for the Glaciotectonic Map of North America are made available for scientific and educational purposes without copyright or use restrictions. Modification and repackaging of these data are allowed; any publication or distribution of resulting products should acknowledge the published map (Aber et al. 1995) and should indicate DASC/KGS as the data source. For any questions concerning digital data, contact James S. Aber.

References

Aber, J.S., Bluemle, J.P., Brigham-Grette, J., Dredge, L.A., Sauchyn, D.J. and Ackerman, D.L. 1993. Glaciotectonic data base and mapping of North America. In Aber, J.S. (ed.), Glaciotectonics and mapping of glacial deposits. Canadian Plains Research Center, Canadian Plains Proceedings 25 (vol. 1), p. 177-200. Regina, Canada.
Aber, J.S., Bluemle, J.P., Brigham-Grette, J., Dredge, L.A., Sauchyn, D.J. and Ackerman, D.L. 1995. Glaciotectonic map of North America, scale 1:6,500,000. Geological Society of America, Maps and Charts Series, MCH 079.
Douglas, R.J.W. 1969. Geological map of Canada. Geological Survey Canada, Map 1250A, 1:5,000,000.
Dyke, A.S. and Prest, V.K. 1986. Late Wisconsinan and Holocene retreat of the Laurentide Ice Sheet. Geological Survey Canada, Map 1702A, 1:5,000,000.

GIS Data -- ID Numbers

GLACIOTECTONIC DATA

Basement faults:: Known, continuous (K-C) -- 10; Known, discontinuous (K-D) -- 12; Suspected, continuous (S-C) -- 15; Suspected, discontinuous (S-D) -- 17
Concealed features:: Known, continuous (K-C) -- 20; Known, discontinuous (K-D) -- 22; Suspected, continuous (S-C) -- 25
Ice-shoved hills:: Known, continuous (K-C) -- 30; Known, discontinuous (K-D) -- 32; Suspected, continuous (S-C) -- 35; Suspected, discontinuous (S-D) -- 37
Source basins:: Known, center of basin (K) -- 40; Suspected, center of basin (S) -- 45
GEOLOGIC BOUNDARIES: Canadian Shield -- 110; Appalachian Mountains -- 120; Rocky Mountains -- 130; Continental shelf (-1000 m) -- 140
GLACIAL LIMITS: L. Wisc. Laurentide limit -- 210; L. Wisc. Cordilleran limit -- 220; Pre-Wisc. central U.S.A. limit -- 230; L. Wisc. large nunataks -- 240 and 241; Alaskan maximum limit -- 250; Selected city -- 810

GAGE Homepage

For more information, contact:

J.S. Aber, e-mail: aberjame@esumail.emporia.edu

Last update: April 2003.