A geographic information system (GIS) allows combining and overlaying of layers for analysis of spatial relations not readily apparent in the standard paper publication. This disc contains only geology. However, digital data on geology, geophysics, and geochemistry can be combined to create useful derivative products-- for example, see Phillips and others (1993).
This CD-ROM contains a copy of the text and figures from Professional Paper 901 by King and Beikman (1974a). This text describes the historical background of the map, details of the compilation process, and limitations to interpretation. The digital version of the text can be searched for keywords or phrases.
For other types of computer users, the map must be converted from one of the following formats included on the CD-ROM:
ARC/INFO 6.1.1 Export Digital Line Graph (DLG) Optional Drawing Exchange File (DXF) Map Overlay Statistical System (MOSS)
Construction of a geologic map of an area as large and complex as the conterminous United States requires a great deal of generalization: geologic units shown on larger scale maps are combined into broader map units and their contacts are simplified to produce a pattern that is legible at the scale of publication. The process of generalization used in the compilation of the Geologic Map of the United States is described in King and Beikman (1974a, p. 20).
Furthermore, the Geologic Map of the United States is primarily a bedrock map, which depicts geologic materials present beneath the soil or relatively thin mantles of surficial deposits, not necessarily the surficial materials themselves. For example, the map does not depict the glacial deposits in the northern States, the widespread eolian deposits in the High Plains, and the high-level gravels that mantle older Tertiary and pre-Tertiary units in much of the Atlantic and Gulf Coastal Plains.
The larger geology polygons are split into several smaller polygons to avoid problems with color and pattern fill on screen plots and paper plotters. The maximum polygon size is 1476 vertices, which is PostScript compatible.
The rock-unit names are stored in uppercase letters as well as the published mixed case. For instance:
TMC Tmc TMOE Tmoe UTA uTaThe uppercase names are used in the coverage because an INFO sort in ARC/INFO is case sensitive. The lookup tables must be sorted to work correctly. The mixed-case rock-unit names are in the kbcolor.lut lookup table. Longer rock-unit descriptions such as:
Cretaceous granitic rocks Washita Groupare in the ROCKDESC column of the .pat file of the KBLEG coverage. Some of the unit names have been modified to avoid ambiguity.
The Pennsylvanian symbol is stored as PP in:
PP
PP1
PP1a
PP2
PP3
PP4
The Triassic symbol is stored as Tr in: JTr
Tr
TrPe
Trv
Tri
Trg
The Cambrian symbol is stored as C in: C
Cq
OC
Ce
Cv
Cg
m1 is replaced with mm1 to avoid confusion with M1
m2 is replaced with mm2 to avoid confusion with M2
m3 is replaced with mm3 to avoid confusion with M3
m4 is replaced with mm4 for consistency
The extent of glaciation appears in the legend but is not present in
the coverage.
The Geologic Map of the United States is primarily a bedrock map, which depicts geologic materials present beneath the soil or relatively thin mantles of surficial deposits, not necessarily the surficial materials themselves. For example, the map does not depict the glacial deposits in the northern States, the widespread eolian deposits in the High Plains, and the high-level gravels that mantle older Tertiary and pre-Tertiary units in much of the Atlantic and Gulf Coastal Plains.
The ARC/INFO version of the Geologic Map of the United States consists of three coverages:
1) geology - 12,800 polygons 2) faults - 3 fault types and hidden contacts 3) legend - 164 rock units
The fault coverage has four line types:
1) faults 2) dashed faults 3) dotted faults 4) hidden contacts
The DESC field descriptors are FAULT, DASH, DOT, CONTAC, respectively.
C,cat,Ce,Cg,Cq,Cv,D,D1,D2,D2c,D3,D3c,De,dike,DS,DSe,DSv,Dv,J, Jc,Jg,Jmi,JTr,Kc,Ke,Kg,Kg1,Kg2,Kg3,Kgn,Ki,Kv,lK,lK1,lK2,lK3, lMz,lMze,lMzv,lPz,lPze,lTa,lTf,lTv,M,M1,M2,M3,mm1,mm2,mm3,mm4, Ms,O,O1,O1a,O1b,O2,O3,OC,Oe,Ov,P,P1,P1c,P2,P2a,P2ac,P2b,P3,P3a, P3b,P4,Pe,PP,PP1,PP1a,PP2,PP3,PP4,Pza,Pzg1,Pzg2,Pzg3,Pzmi,Q, Qf,Qh,Qp,Qv,S,S1,S2,S3,Se,SOe,Sv,Ta,Te,Te1,Te2,Te3,Teb,Tec,Tee, Tel,Ti,Tm,Tmc,Tmf,Tmoe,Tmv,To,Toc,Toee,Tp,Tpc,Tpf,Tpv,Tr,Trg, Tri,TrPe,Trv,Tx,Txc,uK,uK1,uK2,uK3,uK3a,uK3b,uK4,uM,uMze,uPz, uPzc,uPze,uTa,W,Wg,Wgn,Wmi,WTER,Wv,X,Xg,Xm,Xv,Y,Y1,Y2,Y3,Ya, Yg1,Yg2,Ygn,Ym,Ymi,Ys,Yv,Z,Zg,Zv
Each line object in the fault coverage has one of four attribute values:
1) faults (label FAULT) 2) dashed fault (label DASH) 3) dotted fault (label DOT) 4) hidden contact (label CONTAC)
Full details of the meanings of the attributes are given in USGS Professional Paper 901, whose text is provided with this data set.
Although all data and software published on this CD-ROM have been used by the USGS, no warranty, expressed or implied, is made by the U.S. Geological Survey as to the accuracy of the data and related materials and/or the functioning of the software. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of this data, software, or related materials.
Graphical map depictions on this disc are intended to be used within the map scale limits applicable to the source data. Although software enables the user to show images on the disc at various scales, the user is cautioned to refer to the source documentation for the appropriate map scale limitations.
This CD-ROM was produced in accordance with the ISO 9660 standard and thus allows access to the map data files and MAPPER by computers with ISO 9660 software drivers.
In addition, the disc contains menu and display programs that operate on DOS-compatible computers with the following configuration:
IBM or compatible personal computer 640 kb RAM (at least 540 kb free memory) Math coprocessor MS- or PC-DOS version 5.0 or later Microsoft MSCDEX version 2.1 or later CD-ROM drive with ISO 9660 software driver Hard disk drive (5 Mb free) Super VGA graphics card (640x480 pixels with 256 colors) VGA color monitor Mouse
Although all data and software published on this CD-ROM have been used by the USGS, no warranty, expressed or implied, is made by the U.S. Geological Survey as to the accuracy of the data and related materials and/or the functioning of the software. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of this data, software, or related materials.
Graphical map depictions on this disc are intended to be used within the map scale limits applicable to the source data. Although software enables the user to show images on the disc at various scales, the user is cautioned to refer to the source documentation for the appropriate map scale limitations.