Digital Geologic Map of Georgia (Ver2)
georgia department of natural resources
environmental protection division
georgia GEOLOGIC survey
Atlanta
1999
DOCUMENTATION REPORT 99-20
Table of Contents
OVERVIEW iii
GLOSSARY iv
PART A - GENERAL DESCRIPTION OF THE GIS DATABASE: 1
1.0 Identification/Background Information 2
2.0 Data Quality 2
2.1 Attribute Accuracy 2
2.2 Logical Consistency 2
2.3 Completeness 2
2.4 Positional Accuracy 2
2.5 Lineage 3
3.0 Spatial Data Organization Information 3
4.0 Spatial Reference Information 3
5.0 Entity and Attribute Information 4
6.0 Distribution Information 4
7.0 Metadata Reference Information 4
APPENDIX A - SIGNATURE 5
PART B - TECHNICAL DESCRIPTION OF THE GIS DATABASE: 7
1.0 Identification/Background Information 8
1.1 Citation 8
1.2 Description 8
1.3 Time Period of Content 9
1.4 Status 9
1.5 Spatial Domain 9
1.6 Keywords 9
1.7 Access Constraints: Distribution constraints, see 1.9 9
1.8 Use Constraints 9
1.9 Point of Contact 10
2.0 Data Quality Information 10
2.1 Attribute Accuracy 10
2.2 Logical Consistency Report: 10
2.3 Completeness Report 10
2.4 Positional Accuracy 11
2.5 Lineage 11
3.0 Spatial Data Organization Information 14
3.2 Direct Spatial Reference Method 14
3.3 Point and Vector Object Information: 14
4.0 Spatial Reference Information 14
4.1 Horizontal Coordinate System Definition: 14
5.0 Entity and Attribute Information 15
5.1 Detailed Description 15
6.0 Distribution Information 15
6.1 Distributor 15
6.2 Resource Description 15
6.3 Distribution Liability 15
6.4 Standard Ordering Process 15
6.5 Custom Order Process 15
7.0 Metadata Reference Information 16
7.1 Metadata Date 16
7.2 Metadata Review Date 16
7.4 Metadata Contact 16
7.5 Metadata Standard Name 16
7.6 Metadata Standard Version 16
Appendix B: Attribute Table 17
Appendix C: List of Changes Made to Digital Geologic Map of Georgia Database 22
PART C - THE DIGITAL FILES CONTAINING THE GIS DATABASE 25
Summary of Contents of CD-ROM 25
Disk Jacket
OVERVIEW
OVERVIEW
This document is a three part documentation report for a Geographic Information System (GIS) database developed with Arc/Info software by the Georgia Geologic Survey (GGS), a branch of the Environmental Protection Division of the Georgia Department of Natural Resources. This documentation report follows the "Content Standards for Digital Geospatial Metadata" (Standards) developed by the Federal Geographic Data Committee (FGDC), published June 8, 1994. As a convenience, Parts A and B employ the outline/headings contained in the Standards. Parts A and B are printed on paper and Part C is composed of digital products. Part B meets the technical requirements of the Standards. Part A is intended as a general purpose summary of the database. Part B is a more technical section included primarily for the benefit of GIS processors. Part C contains the following digital products: a database and the associated documentation, that includes a copy of this publication.
The digital files are written to 1 CD-ROM. A directory of the files and a short explanation is contained in the ASCII file README.ASC on the data disk.
This database was developed to satisfy specific project purposes. Users are advised to read the entire Documentation Report and to evaluate the suitability and limitations of the database for the user's purposes.
GLOSSARY
Arc/Info: a popular GIS software, used by the GGS
ASCII: abbreviation for `American Standard Code for Information Interchange. A set of codes for representing alphanumeric information in a format which any computer can read.
attribute: a characteristic of a geographic feature. For example, if the geographic feature is a river, then the attributes of the river are the river name, the flow rate, the chemical history, etc.
attribute accuracy: a measure of how well the reported characteristics actually match the real-world characteristics of a geographic feature
Compact Disk Read Only Memory (CD-ROM): an optical media which can store 650 Mb of information.
completeness: a description of the relation between the items represented in the database and the real world. For example, if a database contains water wells in Georgia, does it contain all the water wells in Georgia, or a defined subset of wells. If the database contains a defined subset of wells, does it contain every well in Georgia that meets the definition by which the subset was chosen.
Content Standards for Digital Geospatial Metadata: a standard developed by the FGDC which specifies the information content of metadata for a set of digital geospatial data.
CorelDraw: a popular drawing, tracing and editing software, used by the GGS.
database: a logical collection of interrelated information, managed and stored as a unit on a computer or other storage media. A GIS database includes data about the spatial location and shape of geographic features recorded as points, lines, areas, as well as their attributes.
decimal degrees: a unit of measure for geographic coordinates. The conversion formula for decimal degrees is: Decimal Degrees = Degrees + Minutes/60 +Seconds/3600
Department of Natural Resources (DNR): a department of the government of the State of Georgia.
digital: refers to the process of conversion of information into machine language so that a computer can read, write, store, and process the information.
Digital Line Graph (DLG): computer files from the USGS which contain digital maps of transportation, hydrography, contours, and public land survey boundaries.
digital maps: a map is an abstract representation of the physical features of a portion of the Earth's surface graphically displayed on a piece of paper. When that piece of paper is converted into a form which the computer can use, the map is then digital.
Digital Raster Graphic (DRG): computer files from the USGS which is a raster image of a scanned USGS topgraphic map including the collar information, georeferenced to the UTM grid.
diskette: a storage medium, usually measuring 3.5 inches in diameter, which is used to store or transfer information from one computer to another.
Federal Geographic Data Committee (FGDC): an inter-governmental committee established through the Office of Management and Budget and charged with the responsibility to coordinate various surveying, mapping, and spatial data activities to meet the needs of the Nation.
Georgia Geologic Survey (GGS): a branch of the Environmental Protection Division.
Geographic Information System (GIS): an organized collection of computer hardware, software, geographic data, and personnel designed to efficiently capture, store, update, manipulate, analyze, and display all forms of geographically referenced information.
Hypertext Markup Language (HTML): an acronym for Hypertext Markup Language, HTML is the computer language used to create hypertext documents. HTML uses a finite list of tags (which consist of a "<", a "directive", zero or more parameters and a ">" that describe the general structure of various kinds of documents linked together on the World Wide Web.
label points: a single x,y coordinate which identifies an area, and holds a place in the database wherein the area's attribute information is stored.
latitude, longitude: a geographic reference system to locate positions on the Earth. Latitude and longitude are angles measured from the Earth's center to the position on the Earth's surface. Latitude measures angles in a north-south direction, while longitude measure angles in the east-west direction.
lineage: information about the events, parameters, and source data which constructed a geographic database, and information about the responsible parties.
logical consistency: an explanation of the fidelity of the relationships in the database. For example, for a geographic area, do the vector lines which create area boundaries join to encircle the area with no gaps. Or for example, for a particular attribute, are all the values given within a valid range.
longitude, latitude: see latitude, longitude
metadata: information about the content, quality, condition, and other characteristics of a database
National Map Accuracy Standards: a set of standards developed by the USGS which states the level of accuracy required for a map product of a particular scale.
pkzip: a popular data compression software.
positional accuracy: an assessment of how well the reported position of a geographic feature represents the real-world position.
United States Geological Survey (USGS): a branch of the United States Department of Interior
Rich Text Format (RTF): an interchange format from Microsoft for the exchange of documents between Word and other document preparation (Word processing) systems.
vector lines: lines which are described by x,y coordinates and are commonly used to represent linear geographic features. Each linear feature is represented as an ordered list of vertices.
WordPerfect: a popular word processing software.
PART A - GENERAL DESCRIPTION OF THE GIS DATABASE:
DIGITAL GEOLOGIC MAP GEORGIA (Ver. 2)
1.0 Identification/Background Information
This database is an update of the 1996 Digital Geologic Map of Georgia. Usage of the 1996 version revealed several errors in polygons that defined rock units and labels that identified rock units. Errors and omissions in rock units that were found during this update were corrected or added to the original database. In addition, faults, shear and mylonite zones, the Brevard Fault Zone, and diabase dikes that are depicted on the published 1976 Geologic Map of Georgia were not included in the 1996 Digital Geologic Map of Georgia. These latter features are now compiled as three additional, separate databases that may be used in conjunction with the Digital Geologic Map of Georgia. Metadata descriptions contained in the original version of the Digital Geologic Map of Georgia are included here where appropriate.
This database delineates mapped geologic units for the state of Georgia (compiled on a scale of 1:500,000). The map compilation was published by the Georgia Geologic Survey in 1976 as the Geologic Map of Georgia. The majority of rock units were mapped by reconnaissance methods during the year 1973 and represent over 15 man-years of effort. In some areas the more detailed work of previous authors has been included. In these areas the original authors' geologic units were field checked in 1973, and their designations were changed to conform to the general descriptions used in the reconnaissance mapping. The geologic unit descriptions are based on field observations and outcrop or hand specimen identification of rock types. Groupings of rock types within units are based on relative percentages estimated in the field.
This section contains information about the lineage, positional accuracy, attribute accuracy, logical consistency, and completeness of the database.
Attributes (geologic units) were checked by visual inspection through an on-screen comparison of the 1996 Digital Geologic Map of Georgia overlying a scanned version (TIFF image) of a paper copy of the published Geologic Map of Georgia. Suspected errors and omissions were visually confirmed with a paper copy of the published Geologic Map of Georgia, and if necessary, with original compilation maps in the technical files of the Georgia Geologic Survey. Detected errors were corrected. After repeated inspections, it is believed that attribute accuracy approaches 100 percent.
Each of the 174 rock units was selected from the digital database and plotted individually in ArcView. Errors in polygons and linework (arcs) were corrected in Arcedit. A visual inspection for attribute errors was conducted when each rock unit was plotted in ArcView. Geologic units were compared to the scanned image and to a paper copy of the published map . Detected attribute errors were corrected.
This database is complete for the entire state of Georgia.
A positional inaccuracy was detected during compilation of the 1996 database. A map made from the statewide database was overlaid with the mylar copy of the original source map and shows boundary lines between adjoining geologic units to be shifted up to approximately 1/16 inch. At the map scale of 1:500,000, this distance equates to approximately 0.5 miles. The mismatch in the central part of the state is less than at the southern or northern parts of the state. There are several possible sources of error contributing to the shift: the 200% enlargement, which was accomplished by photographic means, uncertainty at the time regarding the source map projection, and the possibility of cartographic mislocation of geographic registration points.
An examination of the tic marks that were manually added to the mylar referenced above shows that several were inaccurately placed. This was probably one source of the positional inaccuracy. Due to the level of effort required to redevelop the entire database and the relatively small magntitude of the error, the positional inaccuracy was not corrected in this version.
This version (Version 2) of the Digital Geologic Map of Georgia uses the original version of the Digital Geologic Map of Georgia as the base map and corrections were added to the digital database. Lineage for the original version of the Digital Geologic Map of Georgia is described in GGS Documentation Report 96-3. Lineage for the revised version of the Digital Geologic Map of Georgia is described as follows:
* The mylar of an unpublished (1975) version of the Geologic Map of Georgia and a paper copy of the 1976 Geologic Map of Georgia were physically overlain with each other and with a line mylar of the 1976 Geologic Map of Georgia that was used to create Version 1 of the Digital Geologic Map of Georgia. No errors were detected in these maps.
* The mylar of the unpublished (1975) version of the Geologic Map of Georgia and a paper copy of the 1976 Geologic Map of Georgia were scanned on a CalComp ScanPlus III 1800T scanner, which is a large format scanner.
* Polygon linework and attributes were viewed at high magnification so that attributes could be checked and corrected.
* Extensive linework was traced in CorelDraw 7.0 at high magnification and exported to ArcInfo 7.2.
* Linework was added to the original geology coverage in Arc and Arcedit
* The new coverage was cleaned and topology built.
* Labels were added and errors identified.
* Linework errors were corrected.
* Attributes were typed in at the keyboard within ArcView. Attribute information was obtained from the published 1976 Geologic Map of Georgia and from Version 1 of the Digital Geologic Map of Georgia.
3.0 Spatial Data Organization Information
This database delineates the geologic units mapped at a scale of 1:500,000 for the entire state of Georgia. The geologic units are represented digitally as polygons, each with a label attributed with the geologic unit symbol.
4.0 Spatial Reference Information
4.1 This database is stored in the Albers Conic Equal Area projection with units in meters. Further information on the specific parameters used can be found in Part B, Section 4.0.
5.0 Entity and Attribute Information
Each polygon in the database has three attributes. One attribute represents the geologic unit symbol, as published on the Geologic Map of Georgia, 1976. Upper case letters represent the Geologic time period or epoch from the geologic time scale (ie. Cambrian, Ordovician, Cretaceous). Lower case letters represent the formation, group, or unit name.
A second attribute is a short description of the rock unit or its formal map unit name. These descriptions are from the published 1976 Geologic Map of Georgia. A listing of the geologic units included in the database is presented in Appendix A as a convenience to the reader. The legend of the published map is not included as a part of this database. The other attribute is used for plotting the geology map so that the colors match the published map as closely as possible. This attribute is a symbol number (from the ARC/INFO calcomp1.shd file) that is coded for each polygon.
This database is available in CD-ROM format from the Georgia Geologic Survey, referenced as GIS-3, Digital Geologic Map of Georgia (Ver. 2). The CD-ROM is available from the information geologist at the e-mail address: Info_Geologist@mail.dnr.state.ga.us.
7.0 Metadata Reference Information
The metadata is incorporated within this publication, DOCUMENTATION REPORT 99-20. Part B is the Technical Section of this publication, which conforms with the "Content Standards for Digital Geospatial Metadata" as defined by the Federal Geographic Data Committee.
Signatures for the GIS Database:
Digital Geologic Map of Georgia (Ver. 2).
********************
Preparation of Database and Documentation Report
Prepared by: ________________________ ___________________
Dr. Mark D. Cocker (Date Signed)
Checked by: ________________________ ___________________
Victoria P. Trent (Date Signed)
********************
Data Source and Data Provider
Prepared by: ________________________ ___________________
Dr. Mark D. Cocker (Date Signed)
Checked by: ________________________ ___________________
Victoria P. Trent (Date Signed)
********************
AUTHORIZATION
The Georgia Geologic Survey of the Environmental Protection Division of the Georgia Department of Natural Resources approves of the release of the GIS database as presented in Parts A, B, and C of the accompanying documentation report.
Authorized by: ________________________ ___________________
B. Roger Carter (Date Signed)
Assistant Branch Chief
PART B - TECHNICAL DESCRIPTION OF THE GIS DATABASE:
DIGITAL GEOLOGIC MAP OF GEORGIA (Ver. 2)
PART B - TECHNICAL DESCRIPTION OF THE DATABASE:
DIGITAL GEOLOGY MAP OF GEORGIA (Ver. 2)
1.0 Identification Information
1.1 Citation
8.1 Originator: Georgia Geologic Survey
8.2 Publication Date: 1999
8.4 Title: DOCUMENTATION REPORT 99-20
Digital Geologic Map of Georgia
8.5 Edition: Version 2
8.6 Geospatial Data
Presentation Form: GIS Database
8.7 Series Name: Digital Geologic Map of Georgia
8.8.1 Publication Place: Atlanta, Georgia
8.8.2 Publisher: Georgia Geologic Survey
8.10 Online Linkage: Not Available
1.2 Description
1.21 Abstract:
This database delineates mapped geologic units for the state of Georgia (compiled on a scale of 1:500,000). The map compilation was published by the Georgia Geologic Survey in 1976 as the Geologic Map of Georgia. The majority of rock units were mapped by reconnaissance methods during the year 1973 and represent over 15 man-years of effort. In some areas the more detailed work of previous authors has been included. In these areas the original authors' geologic units were field checked in 1973, and their designations were changed to conform to the general descriptions used in the reconnaissance mapping. The geologic unit descriptions are based on field observations and outcrop or hand specimen identification of rock types. Groupings of rock types within units are based on relative percentages estimated in the field.
This version of the database corrects errors in the original version of the Digital Geologic Map of Georgia that have become apparent through use of that version. Corrections are listed in Appendix C.
1.2.2 Purpose:
This GIS database was developed for the Environmental Protection Division for use in analysis to support EPD's environmental protection programs.
1.3 Time Period of Content
9.1.1 Calendar Date: 1976
1.3.1 Currentness Reference: ___,1976. Geologic Map of Georgia, Georgia Geologic Survey SM-3, one sheet. Scale 1:500,000.
1.4 Status
1.4.1 Progress: Complete
1.4.2 Update Frequency: none planned
1.5 Spatial Domain
1.5.1 Bounding Coordinates
1.5.1.2 West Bounding Coordinate: -85.60454505
1.5.1.3 East Bounding Coordinate: -80.74251641
1.5.1.3 North Bounding Coordinate: 34.98247828
1.5.1.4 South Bounding Coordinate: 30.33398562
1.6 Keywords
1.6.1 Theme
1.6.1.1 Theme Keyword Reference: none
1.6.1.2a Theme Keyword: geology
1.6.1.2b Theme Keyword: lithology
1.6.1.2c Theme Keyword: geologic maps
1.6.1.2d Theme Keyword: surficial geology
1.6.2 Place
1.6.2.2a Place Keyword: GA
1.6.2.2b Place Keyword: Georgia
1.6.2.2c Place Keyword: USA
1.7 Access Constraints: Distribution constraints, see 1.9
1.8 Use Constraints: Scale 1:500,000
1.9 Point of Contact
10.1.1 Contact Person: Information Geologist
10.1.2 Contact Organization: Georgia Geologic Survey
10.3 Contact Postion: Information Geologist
10.4. Contact Address
10.4.2a Address: Agriculture Building, Rm 400
10.4.2b Street: 19 Martin Luther King, Jr Boulevard
10.4.3 City: Atlanta
10.4.4 State: Georgia
10.4.5 Postal Code: 30334
10.4.6 Country: USA
10.5 Contact Voice Telephone: (404) 656-3214
10.7 Contact Facsimilie Telephone: (404) 657-8379
10.8 Contact Electronic Mail Address: Info_Geologist@mail.dnr.state.ga.us
10.9 Hours of Service: 8:00 a.m. - 4:30 p.m. EST
2.0 Data Quality Information
2.1 Attribute Accuracy
2.1.1 Attribute Accuracy Report:
Attributes (geologic-units) were checked by visual inspection through an on-screen comparison of the 1996 Digital Geologic Map of Georgia overlying a scanned version (TIFF image) of a paper copy of the published Geologic Map of Georgia. Suspected errors and omissions were visually confirmed with a paper copy of the published Geologic Map of Georgia, and if necessary, with original compilation maps in the technical files of the Georgia Geologic Survey. Detected errors were corrected. After repeated inspections, it is believed that attribute accuracy approaches 100 percent.
2.2 Logical Consistency Report:
Polygon topology is present.
2.3 Completeness Report:
This database covers the entire state of Georgia.
2.4 Positional Accuracy:
Vector accuracy is believed to be accurate within 0.5 mile.
2.5 Lineage
2.5.1a Source Information
2.5.1.1 Source Citation: Georgia Geologic Survey
2.5.1.2 Source Scale Denominator: 500,000
2.5.1.3 Type of Source Media: publication mylar for the 1976 Geologic Map of Georgia used to prepare Version 1 of the Digital Geologic Map of Georgia.
2.5.1.5 Source Citation Abbreviation: GGS
2.5.1.6 Source Contribution: Used to check for errors in Version 1.
For Version 1, GGS performed data processing into Arc/Info of the data, documented the data to GGS standards, and published the data.
2.5.1b Source Information
2.5.1.1 Source Citation: Georgia Geologic Survey
2.5.1.2 Source Scale Denominator: 500,000
2.5.1.3 Type of Source Media: Version 1 of the Digital Geologic Map of Georgia
2.5.1.5 Source Citation Abbreviation: GGS
2.5.1.6 Source Contribution:
Version 1 of the Digital Geologic Map of Georgia was compared with other cited sources both on-screen and with hard (paper) copies by the GGS.
2.5.1c Source Information
2.5.1.1 Source Citation: Georgia Geologic Survey
2.5.1.2 Source Scale Denominator: 500,000
2.5.1.3 Type of Source Media: Scanned image of the 1976 Geologic Map of Georgia.
2.5.1.5 Source Citation Abbreviation: GGS
2.5.1.6 Source Contribution: Used to check for errors in Version 1.
Compared on-screen with Version 1 of the Digital Geologic Map of Georgia. Corrections included in Version 2 were performed by the GGS. The GGS documented the revised data to GGS standards, and published the data.
2.5.2a Process Information:
Procedures used to create or automate data:
Process information for the original version of the Digital Geologic Map of Georgia is documented in GGS Documentation Report 96-3.
The mylar of an unpublished (1975) version of the Geologic Map of Georgia and a paper copy of the 1976 Geologic Map of Georgia were physically overlain with each other and with a line mylar of the 1976 Geologic Map of Georgia that was used to create Version 1 of the Digital Geologic Map of Georgia. No errors were detected in these maps.
The mylar of the unpublished (1975) version of the Geologic Map of Georgia and a paper copy of the 1976 Geologic Map of Georgia were scanned on a CalComp ScanPlus III 1800T scanner, which is a large format scanner.
All images were created in RASTER format by the scanners and saved as TIFF files.
These images were geographically registered using the REGISTER and RECTIFY commands in Arc. Procedures are described in Arc/Info 7.2 Help.
Tics were registered in Albers Conic Equal Area meters.
These images were found to precisely overlie each other on-screen.
Errors and omissions (excluding faults and diabase dikes) were checked on-screen.
The process involved selecting and plotting each of the 174 rock units depicted on the printed Geologic Map of Georgia (Georgia Geologic Survey, 1976) individually in ArcView 3.1.
These were then visually compared with the scanned TIFF image of the paper copy of the 1976 Geologic Map of Georgia.
Suspected errors were cross-checked with a hard (paper) copy of the 1976 Geologic Map of Georgia.
Some errors were traced to errors in printing of the 1976 Geologic Map of Georgia. These errors were cross-checked with original 1:250,000 scale compilation maps used to prepare the 1976 Geologic Map of Georgia and with original county-scale field maps where available. This error-checking process was aided by Bruce O'Connor who helped prepare the 1976 Geologic Map of Georgia.
Several types of errors or omissions were detected and corrected through several techniques.
Types of errors or omissions include: 1) missing polygons; 2) missing contacts that divided one polygon (map unit) into two or more new polygons (map units); 3) incorrect map unit attributes; 4) missing map unit attributes.
Map unit attributes were also added where new polygons were added or created as in the errors #1 and #2.
Missing polygons and extensive or long contacts (greater than a few miles) were added by the following processes.
The arcs/contacts and registration tics were traced in CorelDraw 7.0 under high magnification using the scanned (TIFF) image of the 1976 Geologic Map of Georgia as the base.
The arcs/contacts were exported as .DXF files.
The .DXF files were converted to an ARC/INFO format using the DXFARC command.
Tic coordinates in DD were projected to ALbers COnic Equal Area coordinates using the Project command and a DD to Albers aml program.
Tics were added manually in Arcedit using the ADD command to the arc/contact coverages based on those that were traced. The arcs defining the traced tics were deleted.
An empty tic coverage was created using the CREATE command.
Latitude and longitude in Albers Conic Equal Area coordinates were manually entered in TABLES into the empty .TIC file for each registration point.
Using the TRANSFORM command the files containing the arcs/contacts were converted from scanner units to Albers Conic Equal Area units (meters).
Arcs/contacts were then added to the original geology coverage using the GET command in Arcedit.
Topology was built using the CLEAN command in Arc.
Arcs/contacts that defined entire polygons were added to the original geology coverage through the use of either the UNION or IDENTITY command in Arc.
Topology was built using the BUILD command in Arc.
The NODEERRORS command was used to identify dangles for the added arcs/contacts.
Dangles were corrected manually in Arcedit by selecting and deleting the overshot vector.
The LABELERRORS command was used to check for unlabeled polygons.
Polygon labels were added using the CREATELABELS command.
Items were added or changed in the edit tables function of ArcView 3.1.
The name of the attribute ACODE in Version 1 was changed to GEOLCODE in Version 2 to reflect the nature of the attribute.
Attributes for the GEOLCODE item for the new polygons were manually added in the edit tables function of ArcView 3.1.
Attribute errors and omissions were checked on-screen by plotting each rock unit individually over the scanned TIFF image of the Geologic Map of Georgia.
Attributes for the GEOLCODE item for the mislabeled or unlabeled polygons were manually added in the edit tables function of ArcView 3.1.
These processes identified several errors in the published copy of the Geologic Map of Georgia, also. Those errors included unlabeled units, polygons of the same rock unit with different shading patterns and one polygon with labels for two different rock units. These ambiguities were resolved with the aid of Bruce O'Connor, Georgia Geologic Survey, who had worked on the preparation of the 1976 Geologic Map of Georgia. Ambiguities were resolved by consulting 1:250,000 compilation maps used to prepare the final Geologic Map of Georgia and original field maps.
A total of 60 changes were made to geologic units in the 1996 Digital Geologic Map of Georgia, Version 1. These are listed in Appendix B.
Twenty-nine polygons added.
Four polygons were deleted.
Attributes of 25 existing polygons were changed or added where attributes were lacking.
Contacts of two polygons were modified to reflect that portrayed on the 1976 Geologic Map of Georgia.
Three additional coverages were created for the diabase dikes, faults, and the Brevard Fault Zone. These features were not included in the Digital Geologic Map of Georgia database, but may be used in conjunction with that database.
Victoria Trent, Georgia Geologic Survey, reviewed the final database for attribute and vector errors.
3.0 Spatial Data Organization Information:
3.2 Direct Spatial Reference Method: polygon
3.3 Point and Vector Object Information
3.3.1 SDTS Terms Description:
3.3.1.1 Object Type: polygon
3.3.1.2 Object Count: 3300
3.3.1.1 Object Type: Universe Polygon
3.3.1.2 Object Count: 1
4.0 Spatial Reference Information:
4.1 Horizontal Coordinate System Definition: Albers Conic Equal Area
4.1.1.1 Latitude Resolution:
4.4.4.2 Longitude Resolution:
4.1.1.3 Geographic Coordinate Units: meters
4.1.4 Geodetic Model
4.1.4.1 Horizontal Datum Name: North American Datum of 1927 (NAD27)
4.1.4.2 Ellipsoid Name: Clarke 1866
4.1.4.3 Semi-major Axis: 6378206.4
4.1.4.4 Denominator of Flattening Ratio: 294.98
5.0 Entity and Attribute Information:
5.1 Detailed Description
5.1.1 Entity Type
5.1.1.1 Entity Type Label: geology.pat
5.1.1.2 Entity Type Definition: Polygon attribute table
5.1.2 Attribute
5.1.2.1 Attribute Label: geolcode
5.1.2.2 Attribute Definition: geologic unit symbol
5.1.2.4 Attribute Domain Values: 5 Character alphanumeric
5.1.2 Attribute
5.1.2.1 Attribute Label: symbol
5.1.2.2 Attribute Definition: symbol number for plotting rock units (from calcomp1.shd)
5.1.2.4 Attribute Domain Values: 3 Character integer
5.1.2 Attribute
5.1.2.1 Attribute Label: description
5.1.2.2 Attribute Definition: brief description of the map unit or map unit name
5.1.2.4 Attribute Domain Values: 70 Character alphanumeric
6.0 Distribution Information:
6.1 Distributor: See Point of Contact, 1.9
6.2 Resource Description: DOCUMENTATION REPORT 99-21
6.3 Distribution Liability: Users must assume responsibility to evaluate the usability of this data for their purposes.
6.4 Standard Ordering Process: Contact the Georgia Geologic Survey, see 1.9
6.5 Custom Order Process: Contact the Georgia Geologic Survey, see 1.9
7.0 Metadata Reference Information:
7.1 Metadata Date: 1999
7.2 Metadata Review Date: 10/5/99, by Victoria Trent, GGS
7.2 Metadata Review Date: 12/2/99 by Roger Carter, GGS
7.4 Metadata Contact:
10.1.1 Contact Person: Mark Cocker
10.1.2 Contact Organization: Georgia Geologic Survey
10.3 Contact Position: Advanced Geologist
10.4 Contact Address
10.4.2 Address: 19 Martin Luther King, Jr. Dr. SW
10.4.3 City: Atlanta
10.4.4 State: Georgia
10.4.5 Postal Code: 30334
10.4.6 Country: USA
10.5 Contact Voice Telephone: (404) 656-3214
10.7 Contact Facsimilie Telephone: (404) 657-8379
10.8 Contact Electronic Mail Address: mark_cocker@mail.dnr.state.ga.us
10.9 Hours of Service: 8:00 a.m. - 4:30 p.m. EST
7.5 Metadata Standard Name: FGDC Content Standards for Digital Geospatial Metadata
7.6 Metadata Standard Version: 6/8/94
APPENDIX B
Each polygon in the database has one attribute representing the lithologic unit symbol, as published on the Geologic Map of Georgia, 1976. Upper case letters represent the Geologic time period or epoch from the geologic time scale, (ex. Cambrian, Ordovician, Cretaceous). Lower case letters represent the formation, group, or unit name.
In addition, each polygon is coded with a symbol number (from the ARC/INFO calcomp1.shd file), used for plotting the geology map so that the colors match the published map as closely as possible.
GEOLCODE SYMBOL GEOLOGIC UNIT
Cc 37 Conasauga Group, Middle Unit possible equivalent of Rutledge Limestone
Ccd 715 Conasauga Group, Upper Unit possible equivalent of Nolichucky
Ccdl 168 Conasauga Group, Lower Unit with dolostone
Cch 307 Chilhowee Formation
Ccls 68 Conasauga Group, Middle Unit including limestone unit
Ccm 332 Conasauga Group, Maynardville Limestone
Ccr 317 Copper Ridge Dolomite
Ccs 63 Conasauga Group, Lower Unit including shale and sandstone unit
Ccsl 38 Conasauga Group, Upper Unit including limestone and shale unit
Cr 170 Rome Formation
Cs 48 Shady Dolomite
Dmu 591 Devonian - Mississippian Undivided
Da 503 Armuchee Chert
Dc 392 Chattanooga Shale
Dfm 439 Frog Mountain
Ec 36 Claiborne Undifferentiated
Ecl 171 Clinchfield Sand
Ecm 89 Copper Marl
Ei 64 Irwinton Sand
Eli 120 Lisbon Formation
Em 186 McBean Formation
Eo 70 Ocala Limestone
Eo-Os 75 Eocene and Oligocene Residuum, Undifferentiated
Es 155 Sandersville Limestone
Eta 184 Tallahatta Formation
Etw 151 Twiggs Clay
Eu 135 Eocene Undifferentiated
Kb 781 Blufftown Formation
Kc 760 Cusseta Sand
Kcbe 758 Cusseta, Blufftown and Eutaw Formations, Undifferentiated
Ke 790 Eutaw Formation
Kp 764 Providence Sand
Kr 783 Ripley Formation
Kt 732 Tuscaloosa Formation
Mb 99 Bangor Limestone
Mfp 9 Fort Payne Chert
Mfs 32 Floyd Shale
Mh 104 Hawthorn Formation
Ml 43 Unnamed Limestone Member of Floyd Shale in Floyd County
Mls 792 Lavender Shale Member
Mu 10 Mississippian Undifferentiated
Nm 727 Miccosukee Formation
Nu 729 Neogene Undifferentiated
OCk 112 Knox Group Undifferentiated
Oa 60 Athens Shale
Oc 76 Chickamauga Group Undivided
Och 96 Chota Formation
Oh 255 Holston Limestone
Ol 220 Lenoir Limestone
Omb 61 Middle Ordovician Rocks
On 367 Newala Limestone
Or 156 Rockmark Slate
Os 65 Suwannee Limestone and its Residuum
Oum 188 Upper Ordovician Rocks
Pps 49 Pleistocene - Pliocene Sands and Gravel
Pc 443 Clayton Formation
Pcd 90 Charlton Formation and Duplin Marl
Pcn 427 Nanafalia, Porters Creek and Clayton Formations, Undifferentiated
Plg 538 Gizzard Formation
Pls 424 Sewanee Sandstone
Pnf 440 Nanafalia Formation
Ptu 683 Tuscahoma Sand
Pu 536 Pennsylvanian Undifferentiated
Qal 24 Stream Alluvium and undifferentiated terrace deposits
Qas 716 Aeolian Sand Deposits - formless deposits
Qhi 57 Holocene Shoreline Complex - barrier island facies
Qhm 19 Holocene Shoreline Complex - marsh and lagoonal facies
Qpai 55 Princess Anne Shoreline Complex - barrier island facies
Qpam 720 Princess Anne Shoreline Complex - marsh and lagoonal facies
Qpd 716 Aeolian Sand Deposits - parabolic dunes
Qpmi 721 Pamlico Shoreline Complex - barrier island facies
Qpmm 711 Pamlico Shoreline Complex - marsh and lagoonal facies
Qpni 735 Penholoway Shoreline Complex - barrier island facies
Qpnm 47 Penholoway Shoreline Complex - marsh and lagoonal facies
Qsbi 719 Silver Bluff Shoreline Complex
Qti 51 Talbot Shoreline Complex - barrier island facies
Qtm 20 Talbot Shoreline Complex - marsh and lagoonal facies
Qwi 718 Wicomico Shoreline Complex - barrier island facies
Qwm 17 Wicomico Shoreline Complex - marsh and lagoonal facies
Srm 374 Red Mountain Formation
TKu 722 Lower Tertiary-Cretaceous Undifferentiated
WATER 504 Water
bg1 138 Biotite Gneiss
bg2 283 Biotite Gneiss/Amphibolite
bg3 315 Biotite Gneiss/Hornblende Gneiss/Granite Gneiss
bg4 347 Biotite Gneiss/Mica Schist
c1 218 Mylonite & Ultramylonite
c2 309 Flinty Crush Rock
fg1 110 Biotite Gneiss/Feldspathic Biotite Gneiss
fg1a 731 Biotite Granite, Gneiss/Feldspathic Biotite Gneiss/Amphibolite-Hornblende Gneiss
fg2 79 Biotitic Gneiss Undifferentiated
fg3 45 Biotitic Gneiss/Mica Schist/Amphibolite
fg4 54 Biotitic Gneiss/Amphibolite
gg1 350 Granitic Gneiss Undifferentiated
gg2 334 Granite Gneiss/Gneissic Granite (Augen or Porphyritic)
gg3 301 Muscovite Granite Gneiss
gg4 300 Granite Gneiss/Amphibolite
gg5 319 Calc-Silicate Granite Gneiss
gg6 302 Granite Gneiss/Granite
gr1 108 Granite Undifferentiated
gr1a 129 Non-Porphyritic Granite
gr1b 349 Porphyritic Granite
gr2 175 Granite/Granite Gneiss
gr2a 349 Granite/Gneissic Biotite Granite
gr3 353 Granite/Biotitic Gneiss/Amphibolite
gr4 202 Charnockite
gr5 299 Syenite
m1 685 Marble
m2 681 Calcareous Mica Schist/Micaceous Marble/Mica Schist
mm1 999 Amphibolite
mm10 980 Amphibolite/Metagraywacke/Mica Schist
mm11 41 Mafic Hornfels
mm2 966 Hornblende Gneiss
mm3 967 Hornblende Gneiss/Amphibolite
mm4 771 Hornblende Gneiss/Amphibolite/Granite Gneiss
mm5 752 Hornblende-Biotite Gneiss/Amphibolite
mm6 785 Hornblende Gneiss/Granite Gneiss/Biotite Gneiss
mm7 755 Amphibolite/Epidote Quartzite/Granite Gneiss
mm8 744 Amphibolite/Biotitic Gneiss/Quartz Sericite Schist
mm9 769 Amphibolite/Mica Schist/Biotitic Gneiss
mp1 745 Amphibolite/Gabbro
mp2 747 Gabbro
mp3 762 Amphibolite/Ultramafic
ms1 739 Amphibolitic Schist
ms2 775 Amphibolitic Schist/Amphibolite
ms3 733 Amphibolitic Schist/Amphibolite-Metagraywacke/Mica Schist
mu 1 Undifferentiated Pelitic Rocks
pa1 369 Aluminous Schist
pa2 355 Sillimanite Schist
pa2a 380 Sillimanite Schist/Gneiss
pa2b 378 Sillimanite Schist/Gneiss/Amphibolite
pa2c 432 Sillimanite Schist/Amphibolite
pg1 377 Garnet Mica Schist
pg2 382 Garnet Mica Schist/Gneiss
pg3 486 Garnet Mica Schist/Amphibolite
pm1 67 Metagraywacke Undifferentiated
pm2 66 Metagraywacke/Mica Schist
pm3 167 Metagraywacke/Mica Schist/Calc-Silicate Gneiss
pm3a 133 Metagraywacke/Mica Schist-Quartzite/Amphibolite
pm4 322 Mica Schist/Metasiltstone
pm5 101 Slate/Quartzite/Conglomerate
pm6 73 Conglomerate
pms1 393 Mica Schist
pms2 409 Mica Schist/Amphibolite
pms3 377 Mica Schist/Gneiss
pms3a 395 Mica Schist/Gneiss/Amphibolite
pms4 425 Mica Schist/Quartzite/Gneiss/Amphibolite
pms5 421 Sericite Schist
pms6a 453 Sericite Schist/Amphibolite
pms6b 416 Sericite Schist/Amphibolite/Granite Gneiss
pms6c 480 Sericite Schist/Micaceous Quartzite/Sericite Phyllite
pms6d 478 Quartz Sericite Schist/Biotitic Gneiss
pms6e 436 Quartz Mica Schist/Hornblende Schist/Biotitic Gneiss
pms7 413 Button Mica Schist
pms8 476 Cross-Biotite Schist
pp1 741 Phyllite Undifferentiated
pp1a 372 Meta-Argillite/Phyllite
pp2 368 Graphitic Phyllite
pp3 2 Phyllite and Quartzite
pp3a 664 Phyllite/Quartzite/Calc-Silicate Gneiss
q1 714 Quartzite
q1a 52 Quartzite/Mica Schist
q1b 59 Quartzite/Mica Schist/Amphibolite
q1c 717 Quartzite/Metagraywacke
q1d 713 Quartzite/Phyllite
q2 26 Quartzite/Biotite Granite Gneiss
q3 28 Epidote Quartzite/Amphibolite/Sericite Schist/Biotite Granite
um 787 Ultramafic Rocks Undifferentiated
v1 813 Mafic to Intermediate Metavolcanic Rocks
v2 761 Metadacite
v3 710 Felsic Metavolcanics
v4 777 Undifferentiated Metavolcanics/Sericite Phyllite/Meta-Argillite
v5 810 Meta-Argillite/Sericite Phyllite/Metavolcanics
APPENDIX C
LIST OF CHANGES MADE TO DIGITAL GEOLOGIC MAP OF GEORGIA DATABASE.
1.Added Ptu polygon in Randolph-Terrell Counties.
2. Added contact between Ptu and Ec in Clay-Randolph-Webster Counties. Previously unit was entirely Ptu.
3. Added arc to split pms3a to fg3 and pms3a (Coweta County).
4. Added arcs to split fg1a to gg4, gr1 and fg1a (Greene and Putnam Counties).
5. Added nine um polygons (Murray and Morgan Counties).
6. Added arc to split gg1 to gg1 and q1d (Pickens County).
7. Added arc to split fg1 to fg1 and mm1 (Banks County).
8. Changed attribute of two fg3 to water (Lumpkin County).
9. Changed attribute of mm1 to gg1 (Douglas, Coweta and Heard Counties).
10. Added arc to split pm4 to two pm4 and mu (Pickens County)
11. Changed attribute of three m1 to three pp1 (Cherokee and Bartow Counties).
12. Changed attribute of pa2 to pa2a (Hart County)
13. Changed attribute of two pg1 to two m3 (Cherokee and Bartow Counties).
14.Changed attribute of pg3 to gg2 (Pickens County)
15. Added arc to split gg1 to gg1 and q2 (Stephens County)
16. Added arc to split pms3a to pms3a and pms1 (Meriwehter, Talbot and Harris Counties).
17. Added arc to split pms2 to pms2 and pms5 (Cherokee County).
18. Added arc to split pms3 to pms3 and pms5 (Cherokee County).
19. Changed attribute of six pms5 to six pms6 (Columbia, McDuffie and Warren Counties).
20. Added arc to split pms6 to pms6 and bg1 (Paulding County).
21. Added arc to split Eu to Eu and Kr (Peach and Crawford Counties).
22. Added arc to split Eu to Eu and Kr (Peach and Crawford Counties).
23. Added arc to split bg1 to bg1 and Kt (Muscogee County).
24. Changed attribute of pms6a to pms3a Wilkens County).
25. Added arc to split Qpnm to Qpnm and Qtm (Effingham and Chatham ).
26. Deleted three Qhm (were swamp or small ponds) (Liberty County).
27. Added arc to split Qpam to Qpam and Qhm (McIntosh County).
28. Added arc to split Qhm to Qhm and Qpam (Peach and Crawford Counties).
29. Deleted unknown polygon in Rabun Co. (not labeled and did not correspond to geologic maps in files).
30. Attributed unknown polygon to fg1 (Hart County).
31. Attributed three unknown polygons to mm8 (Elbert County).
32. Attributed two unknown polygons to v3 (Elbert County).
33. Attributed unknown polygon to v2 (Elbert County).
34. Modified pa2c polygon in Douglas County.
35. Altered contact between gg2 and fg3 in Douglas County.
36. Added arc to split mm1 to mm1 and mm4 (Barrow County).
PART C - THE DIGITAL FILES CONTAINING THE GIS DATABASE:
DIGITAL GEOLOGIC MAP OF GEORGIA (Ver. 2)
PART C - THE DIGITAL FILES CONTAINING THE GIS DATABASE: DIGITAL GEOLOGIC MAP OF GEORGIA (Version 2).
SUMMARY STATEMENT / DESCRIPTION OF THE CONTENTS OF PART C
The digital files are written on the enclosed CD-ROM. The disk contains:
1. READ.ME - an ascii file which is a digital copy of this summary.
2. DOCUMENT.ASC - an ascii file which is a digital copy of this publication.
3. DOCUMENT.HTML - a digital copy of this publication in html format.
4. GEOLOGY.E00 - the GIS database of GEOLOGY in ARC/INFO export format.
