DIABASE DIKES IN GEORGIA georgia department of natural resources environmental protection division georgia GEOLOGIC survey Atlanta 1999 DOCUMENTATION REPORT 99-21 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 3 6.0 Distribution Information 3 7.0 Metadata Reference Information 3 APPENDIX A - SIGNATURE 4 PART B - TECHNICAL DESCRIPTION OF THE GIS DATABASE: 6 1.0 Identification/Background Information 7 1.1 Citation 7 1.2 Description 7 1.3 Time Period of Content 7 1.4 Status 8 1.5 Spatial Domain 8 1.6 Keywords 8 1.7 Access Constraints: Distribution constraints, see 1.9 8 1.8 Use Constraints 8 1.9 Point of Contact 8 2.0 Data Quality Information 9 2.1 Attribute Accuracy 9 2.2 Logical Consistency Report: 9 2.3 Completeness Report 9 2.4 Positional Accuracy 9 2.5 Lineage 9 3.0 Spatial Data Organization Information 11 3.1 Indirect Spatial Reference Method 11 3.2 Direct Spatial Reference Method 11 3.3 Point and Vector Object Information: 11 4.0 Spatial Reference Information 11 4.1 Horizontal Coordinate System Definition: 11 5.0 Entity and Attribute Information 12 5.1 Detailed Description 12 6.0 Distribution Information 12 6.1 Distributor 12 6.2 Resource Description 12 6.3 Distribution Liability 12 6.4 Standard Ordering Process 12 6.5 Custom Order Process 12 7.0 Metadata Reference Information 12 7.1 Metadata Date 12 7.2 Metadata Review Date 12 7.4 Metadata Contact 12 7.5 Metadata Standard Name 13 7.6 Metadata Standard Version 13 PART C - THE DIGITAL FILES CONTAINING THE GIS DATABASE 14 Summary of Contents of Disk 15 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: DIABASE DIKES IN GEORGIA 1.0 Identification/Background Information This database is part of an update of the original version of the Digital Geologic Map of Georgia (1996). This database contains the map unit, diabase dikes, which was not included in the original version of the Digital Geologic Map of Georgia. Other changes and updates are contained in the Digital Geologic Map of Georgia (Version 2), the Digital Fault Map of Georgia, and the Brevard Fault Zone in Georgia databases. This database delineates the geologic map unit, diabase dikes, which was mapped at a scale of 1:500,000, for the state of Georgia. These dikes are depicted on the 1976 Geologic Map of Georgia published by the Georgia Geologic Survey. Metadata for the original version and version 2 of the Digital Geologic Map of Georgia are included in GGS Documentation Report 96-3 and 99-20 respectively. This database delineates diabase dikes for the state of Georgia. The diabase dikes were included on the Geologic Map of Georgia, compiled at a scale of 1:500,000, which was published by the Georgia Geologic Survey in 1976. The majority of rock units were mapped by reconnaissance methods during the year 1973 and represent over 15 man-years of effort. Descriptions of the diabase dikes are based on field observations and megascopic identification of the diabase. 2.0 Data Quality This section contains information about the lineage, positional accuracy, attribute accuracy, logical consistency, and completeness of the database. 2.1 Attribute Accuracy No attributes are assigned. 2.2 Logical Consistency Lines representing the diabase dikes were plotted in ArcView. These lines were visually compared to the scanned image (TIFF image), a paper copy of the Geologic Map of Georgia, and the Digital Geologic Map of Georgia (Version 2). Detected errors were corrected in Arcedit. 2.3 Completeness This database was completed for the entire state of Georgia. 2.4 Positional Accuracy Diabase dikes are depicted as lines having a common width on the 1976 Geologic Map of Georgia regardless of their actual width. The dikes were traced in CorelDraw 7 on an underlying scanned version (TIFF image) of a paper copy of the published Geologic Map of Georgia. These were visually checked from a hard copy of the Geologic Map of Georgia and on-screen in Arcview. Detected errors were corrected in Arcedit by reference to a backcoverage of the Digital Geologic Map of Georgia. Arcs were either shifted by the MOVE command or redrawn. Positional accuracy relative to the Digital Geologic Map of Georgia approaches 100 percent. A positional inaccuracy was detected during compilation of the 1996 database for the original version of the Digital Geologic Map of Georgia as described below. As the diabase dikes were drawn to conform with the Digital Geologic Map, the positional inaccuracy would also pertain to the diabase dikes. 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. 2.5 Lineage Lineage for the original version of the Digital Geologic Map of Georgia is described in GGS Documentation Report 96-3. Lineage for Version 2 of the Digital Geologic Map of Georgia is described in GGS Documentation Report 99-20. Lineage for the Diabase Dikes in Georgia is described as follows: * A paper copy of the 1976 Geologic Map of Georgia was scanned on a CalComp ScanPlus III 1800T scanner, which is a large format scanner. * Linework, representing the diabase dikes, was traced over the scanned (TIFF) image of the 1976 Geologic Map of Georgia in CorelDraw 7.0 at high magnification. * Linework was exported to ArcInfo 7.2. * Arcs, depicting the diabase dikes, were checked in ArcEdit for positional accuracy relative to Version 2 of the Digital Geologic Map of Georgia. * Errors were corrected. * The new coverage was cleaned and arc topology was built. * No attributes were added. 3.0 Spatial Data Organization Information This database delineates the geologic unit, diabase dikes, mapped at a scale of 1:500,000 for the entire state of Georgia. The dikes are represented digitally as arcs. 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 No descriptions are listed on the Geologic Map of Georgia (1976), so none are included here. 6.0 Distribution Information This database, referenced as GIS-3, Diabase Dikes in Georgia, is available for distribution from the Georgia Geologic Survey through the Information Geologist. The Information Geologist can be reached through the e-mail address in Part B of this documentation report. 7.0 Metadata Reference Information The metadata is incorporated within this publication, DOCUMENTATION REPORT 99-20. Part B, the Technical Section of this publication, meets the "Content Standards for Digital Geospatial Metadata" as defined by the Federal Geographic Data Committee. APPENDIX A - SIGNATURE Signatures for the GIS Database: Diabase Dikes in Georgia ******************** 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: DIABASE DIKES IN GEORGIA PART B - TECHNICAL DESCRIPTION OF THE DATABASE: DIABASE DIKES IN GEORGIA 1.0 Identification Information 1.1 Citation 8.1 Originator: Georgia Geologic Survey 8.2 Publication Date: 1999 8.4 Title: DOCUMENTATION REPORT 99-21 Diabase Dikes in Georgia 8.5 Edition: Version 2 8.6 Geospatial Data Presentation Form: GIS Database 8.7 Series Name: Diabase Dikes in 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 the geologic unit diabase dikes mapped at a scale of 1:500,000, for the state of Georgia. This rock unit is depicted on the Geologic Map of Georgia published by the Georgia Geologic Survey in 1976. As part of the reconnaissance mapping during the year 1973, diabase dikes were included with the other rock units on the Geologic Map of Georgia. Descriptions of the dikes are based on field observations and megascopic identification of the rock type. Other similarly appearing rock types may be included as diabase dikes. This database adds the diabase dikes omitted during preparation of the original version of the Digital Geologic Map of Georgia. This database is designed to be used in conjunction with Version 2 of the Digital Geologic Map of Georgia. 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: -84.80338789 1.5.1.3 East Bounding Coordinate: -82.51970961 1.5.1.3 North Bounding Coordinate: 34.84494622 1.5.1.4 South Bounding Coordinate: 32.61496085 1.6 Keywords 1.6.1 Theme 1.6.1.1 Theme Keyword Reference: none 1.6.1.2a Theme Keyword: diabase 1.6.1.2b Theme Keyword: dikes 1.6.1.2c Theme Keyword: geology 1.6.1.2d Theme Keyword: lithology 1.6.1.2e Theme Keyword: geologic maps 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: This database contains no attributes. 2.2 Logical Consistency Report: Arc 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: Version 2 of the Digital Geologic Map of Georgia 2.5.1.5 Source Citation Abbreviation: GGS 2.5.1.6 Source Contribution: Positional accuracy of the arcs in the diabase dikes database was checked and corrected with regard to their position relative to the geology as depicted in Version 2 of the Digital Geologic Map of Georgia. 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: Scanned image of the 1976 Geologic Map of Georgia. 2.5.1.5 Source Citation Abbreviation: GGS 2.5.1.6 Source Contribution: Used by the GGS to trace positions of dikes in CorelDraw. Also used by the GGS to check completeness of traced dikes when imported into ArcInfo. 2.5.2a Process Information: Procedures used to create or automate data: 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 the original version of the Digital Geologic Map of Georgia. No errors were detected in these maps. 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. Tics were registered in Albers Conic Equal Area meters. Arcs delineating the diabase dikes and registration tics were traced in CorelDraw 7.0 on-screen under high magnification using the scanned (TIFF) image of the 1976 Geologic Map of Georgia as the base. The arcs were exported as .DXF files. The .DXF files were converted to an ARC/INFO format using the DXFARC command. 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). Topology was built using the BUILD command in Arc. Positional accuracy was visually checked on-screen by plotting the diabase dikes over the scanned TIFF image of the Geologic Map of Georgia. Errors were corrected in Arcedit by shifting the arc with the MOVE command or redrawing the arc with the ADD command. The NODEERRORS command was used to identify dangles for the added arcs. No errors were found. This database contains no labels. 3.0 Spatial Data Organization Information: 3.2 Direct Spatial Reference Method: vector 3.3 Point and Vector Object Information 3.3.1 SDTS Terms Description: 3.3.1.1 Object Type: arc 3.3.1.2 Object Count: 105 4.0 Spatial Reference Information: 4.1 Horizontal Coordinate System Definition: Albers Conic Equal Area Albers_Conical_Equal_Area Standard_Parallel: 29.5 Standard_Parallel: 45.5 Longitude_of_Central_Meridian: -83.5 Latitude_of_Projection_Origin: 23 False_Easting: 0.00000 False_Northing: 0.00000 4.1.1.3 Geographic Coordinate Units: meters 4.1.4 Geodetic Model 4.1.4.1 Horizontal Datum Name: North American Datum of 1983 (NAD83) 4.1.4.2 Ellipsoid Name: GRS 80 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: dike.aat 5.1.1.2 Entity Type Definition: Arc attribute table 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: 10/12/99, by Victoria Trent, GGS 7.2 Metadata Review Date: 12/xx/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 PART C - THE DIGITAL FILES CONTAINING THE GIS DATABASE: DIABASE DIKES IN GEORGIA) PART C - THE DIGITAL FILES CONTAINING THE GIS DATABASE: DIABASE DIKES IN GEORGIA. 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. DIKES.E00 - the GIS database of DIKES in ARC/INFO export format.