Digital geologic map of Lawton quadrangle, southwestern Oklahoma

                          (diskette 3 of 3)



        U.S. Geological Survey Open-File Report 96-376



Directory   / (root) a_readme.1st  file:





                                ABSTRACT



   This diskette contains digital data sets and accompanying

documentation for geologic faults, anticlines, synclines, and

monoclines of the 1:250,000-scale Lawton quadrangle, Oklahoma.  The

original data are from the Geologic Map, sheet 1 of 4, included in the

Oklahoma Geological Survey publication, Reconnaissance of the water

resources of the Lawton quadrangle, southwestern Oklahoma, Hydrologic

Atlas 6, Havens, 1977.  The geologic features on sheet 1 were compiled

by R.O. Fay, 1967-68 and J.S. Havens, 1973.

                                         

                                INTRODUCTION



   This diskette contains digital data sets and accompanying

documentation for geologic faults, anticlines, synclines, and

monoclines of the 1:250,000-scale Lawton quadrangle, Oklahoma.  The

original data are from the Geologic Map, sheet 1 of 4, included in the

Oklahoma Geological Survey publication, Reconnaissance of the water

resources of the Lawton quadrangle, southwestern Oklahoma, Hydrologic

Atlas 6, Havens, 1977.  The geologic features on sheet 1 were compiled

by R.O. Fay, 1967-68 and J.S. Havens, 1973.



   The data are provided both in a nonproprietary and ARC/INFO export

file format.  ARC/INFO software was used in the development of these

data sets (ESRI, 1995).  The use of trade names is for descriptive

purposes only, and does not imply endorsement by the U.S. Government.

ARC/INFO software was used in the development of the data sets, and

the ARC/INFO original-format files are provided for users'

convenience.



   All references to file names, directories, and pathnames in this

document are enclosed in quotation marks.  Pathnames use MS-DOS-style

naming conventions, with the "\" character indicating the highest-

level directory of the diskette.  



   Compilation of the data sets on this diskette was funded under a

cooperative Joint Funding Agreement between the U.S. Geological Survey

and the State of Oklahoma, Office of the Secretary of Environment.



                            FILE FORMATS



   The data set files with ".gz" extensions were compressed for

distribution on the diskette.  The data under the "\arc_data"

directory are in ARC/INFO export file format.  These files need to be

uncompressed to access the digital data. The file "\gzip\gunzip.exe"

is an MS-DOS executable program included on this diskette that will

uncompress the data files. To uncompress a file, type "gunzip -a" and

the file name. Then the file should be renamed to its original name.

For example:



gunzip -a geology.gz

rename geology geology.e00



   The data sets under the "\pd_data" directory are stored in the

generic, DLG-3 nonproprietary format and have file extensions of

".gz" because they were compressed using the GZIP compression

utility.  Designed for data interchange, the DLG-3 format allows the

simple creation of a vector polygon or line data structure.  The

topological linkages are explicitly encoded for node, area, and line

elements.  The files are composed of 8-bit ASCII characters organized

into fixed logical records of 80 bytes.  A detailed description of the

DLG-3 Optional format may be found in Data User's Guide 3, Digital

Line Graphs from 1:2,000,000-Scale Maps (U.S. Geological Survey 1990).

Table 1 shows the uncompressed file characteristics.



Table 1.  Uncompressed file characteristics.

---------------------------------------------------------------------- 

Directory\              Original     Uncompressed    Uncompressed  

file name               file name    DOS file size   UNIX file size

                                     in bytes        in bytes

----------------------------------------------------------------------

arc_data\clines.gz      clines.e00   104,944         103,011

arc_data\faults.gz      faults.e00   144,028         141,333

pd_data\clines.gz       clines        69,836          68,852

pd_data\faults.gz       faults       104,792         102,884



                           DISKETTE ORGANIZATION



   The diskette is compatible with the MS-DOS operating system.

File names with extensions of ".gz" and ".exe" are binary-format

files.  All other files are ASCII format files.  All ASCII files use

MS-DOS record delimiters (carriage return, line feed) to indicate the

end of lines.  Conversion of record delimiters in these ASCII files

may be necessary for use with operating systems other than MS-DOS.  A

utility such as DOS2UNIX, the FTP file transfer utility, or a text

editor may be used to convert the record delimiters, if needed.  Unix

users may use the following perl script to convert the record

delimiters:



#!/usr/bin/perl -pi.dosbak

s/\r\n$/\n/;



   This diskette is organized into four files and three subdirectories:



\-------|-a_readme.1st  - This file

        |-a_notice.txt  - Liability disclaimer

        |-clines.fgd    - Complete documentation of the sources

        |                 and procedures used to create the anticline,

        |                 syncline, and monocline data set

        |-faults.fgd    - Complete documentation of the sources

        |                 and procedures used to create the faults

        |                 data set

        |-arc_data\     - Data sets in ARC/INFO export file format

        |-pd_data\      - Data sets in nonproprietary DLG-3 format

        |-gzip\         - MS-DOS executables and related files for the

                          GZIP package, which is needed to uncompress

                          the files having a ".gz" extension



                         DATA-SET DOCUMENTATION

     

   Documentation files (known as metadata) for the data sets have 

file extensions of ".fgd".  The documentation files comply with the

Federal Geographic Data Committee (FGDC) Content Standards for Digital

Geospatial Metadata (Federal Geographic Data Committee, 1994).  The

FGDC-compliant metadata files contain detailed descriptions of the

data sets, and include narrative sections describing the procedures

used to produce the data sets in digital form.



   The ARC/INFO versions of the data contain the documentation

information used to create the FGDC-compliant metadata files.  The

DOCUMENT program, an ARC Macro Language program, jointly developed by

the U.S. Geological Survey, the U.S. Environmental Protection Agency,

and Environmental Systems Research Institute, may be used to display,

reference, or update the data documentation files (Nebert, 1994).  The

DOCUMENT program works with ARC/INFO revisions 7.0.2 and 7.0.3.

Although the FGDC-compliant metadata files are intended to document

the DLG-3 nonproprietary-format files as well as the ARC/INFO-format

data sets, the DOCUMENT program produces metadata files that contain

some ARC/INFO-specific terminology.  Users are cautioned not to be

confused by this terminology.  The FGDC-compliant metadata files

should contain enough information to eliminate any confusion caused by

the use of ARC/INFO-specific terminology.



                           GEOMETRIC REGISTRATION



   The Albers Equal Area map projection (Snyder, 1987) is used for the

data sets.  This projection is appropriate for maps of the

conterminous United States because of the visual presentation and

equal-area characteristic, which facilitates areal analysis.  This

projection frequently is used for nationwide digital map data sets.

The projection is cast on the North American Datum of 1983. Table 2

provides map projection information.



This projection slightly distorts shapes and distances (scale) in

order to maintain equal-area properties.  Scale is true along the

standard parallels, which are to the north and south of Oklahoma.

Scale distortion in Oklahoma reaches a maximum of slightly less than

one percent at the northern border of the state (Snyder, 1987.)



------------------------------------------------------------------------------

Table 2.  Albers Equal Area projection parameters



[GRS80, Geodetic Reference System 1980; NAD83, North American Datum 1983]

______________________________________________________________________________



Projection parameters:



   Spheroid                            GRS80

   Datum                               NAD83

   First standard parallel             29 30 00 North

   Second standard parallel            45 30 00 North

   Central meridian                    96 00 00 West

   Latitude of projection origin       23 00 00 North



Coordinate system parameters:



   False easting                       0

   False northing                      0

   Planimetric units of measure        meters

______________________________________________________________________________



                             REFERENCES CITED



Environmental Systems Research Institute, Inc. (ESRI), 1995,

     ARC/INFO Command References, ARC/INFO Version 7.0.3 ArcDoc:

     Redlands, CA.  [online documentation].



Federal Geographic Data Committee, 1994, Content standards for digital

     geospatial metadata (June 8): Federal Geographic Data Committee,

     Washington, D.C., 78 p.



Havens, J.S., 1977, Reconnaissance of the water resources of the             

     Lawton quadrangle, southwestern Oklahoma: Oklahoma Geological

     Survey, Hydrologic Atlas 6, scale 1:250,000, 4 sheets.  (Geology

     on sheet 1 compiled by R.O. Fay, 1967-68 and J.S. Havens, 1973.)



Nebert, D.D., 1994, Design of the distributed spatial data library

     (DSDL) for the Water Resources Division: U.S. Geological Survey

     Open-File Report 94-327, 26 p.



Snyder, J.P., 1987, Map projections--A working manual: U.S. Geological

     Survey Professional Paper 1395, 383 p.



U.S. Geological Survey, 1990, Digital line graphs from 1:2,000,000-

     scale maps, data users guide 3: U.S. Geological Survey National

     Mapping Program Technical Instruction, 70 p.



