Greene, D.C., and Wolfe, W.J. 2000 vector digital data Reston, Virginia U.S. Geological Survey http://water.usgs.gov/lookup/getspatial?geo250k This data set is a digital representation of the printed 1:250,000 geologic maps from the Tennessee Department of Environment and Conservation, Division of Geology. The coverage was designed primarily to provide a more detailed geologic base than the 1:2,500,000 King and Beikman (1974). 1:24,000 scale coverage of the state is available for about 40 percent of the state. Formation names and geologic unit codes used in the coverage are from the Tennessee Division of Geology published maps and may not conform to USGS nomenclature. The Tennessee Division of Geology can be contacted at (615) 532-1500 The data set was developed to determine relative geology at scales suitable for use at a scale 1:250,000. The data set should not be used in situations where positional accuracy is an issue. Procedures_Used: SCANNING THE LINEWORK The Tennessee Division of Geology provided the negatives and/or scribecoats for the west, west-central, east-central, and east map sheets for the 1:250,000 Geologic Map of Tennessee. The negatives for the west and west-cetral sheets were scanned and saved as TIF image files at 400 dpi black and white using a Contex FSS-3012t scanner. Positives were made from the scribecoats for the east-central and east sheets. The positives were scanned using the same system. The resulting images were transferred to a Unix workstation for processing in Arc/Info 7.0. GEO-REFERENCING The original negatives and scribecoats did not have any positional tic marks which could be used for geo-referencing. The 1:250,000 USGS Tennessee state boundary had to be used as a reference. Each of the four scanned images were geo-referenced into the Universal Transverse Mercator Zone 16 coordinate system using the Arc/Info REGISTER command. Because of the lack of positional registration on the source material, positional accuracy cannot be guaranteed. DELINEATION Due to time contraints and personnel shortage, hand delineation of the geologic features was not possible. An automated method of delineation from the scanned data was tested. The images were converted into GRIDs using the Arc/Info IMAGEGRID command. Several attempts at automated delineation were made using the GRIDLINE command. After several variations on command parameters, the resulting linework was acceptable and passed onto the next step. CLEANING The linework resulting from the GRIDLINE command was a good conversion from the raster data, but many problems had to be solved. Because of scanner limitations, some of the closer linework merged together into single lines. These had to be deleted and digitzed by hand. There were many spots where linework had "spider-webbed". This occurred where the linework was close but not close enough to merge and cause the automated delineation to create spurious lines between the actual lines. These extraneous lines were removed as well. After linework errors were corrected, the resulting linework was passed through the SPLINE command in ArcEdit. This smoothed out most of the jagged linework caused by the GRIDLINE command. As a side effect, fault lines were altered where intersected by other linework. Some of these effects were corrected when they were visible on a paper plot while most were left as they were for future correction. After errors were corrected, polygons were built from the linework and then checked for closure. Errors found were corrected and the coverage was rebuilt. This process was repeated for each of the four sheets until all obvious errors were corrected. ATTRIBUTION Once the linework was clean, each line was then tagged as being a nonfault, fault, or metamorphic isograd. During this tagging, more errors were found and corrected. Polygons were attributed with the geologic symbol code found on the printed maps. During this process, more errors were found with unclosed polygons which were fixed and retagged. Each of the four sheets went through this process. Each sheet was then plotted to scale using a custom Arc/Info shadeset designed to mimic the printed shade patterns as closely as possible. This process allowed easier verification of the geologic formation attribution. Any errors in linework, line attribution, and polygon attribution were corrected. Geologic symbol codes were based on the published Tennessee Division of Geology maps and may not conform to USGS nomenclature. MERGING The two sheets for western Tennessee were appended together. The resulting linework at the sheet boundaries had to be cleaned and the map boundaries removed. The polygons were then checked for correct attribution along the map boundary and any errors were corrected. The same process was repeated for the eastern Tennessee sheets. The two resulting coverages where then merged into a single coverage using the same process of removing map boundaries and checking/correcting polygon and line features and attribution. Once all four sheets were merged into a single coverage, all polygons with an area of less than 5,000 square meters were removed. These polygons were impossible to recognize when plotted at scale and, in most cases, were "spider-webbing" errors not found during the inital delineation process. Revisions: Many revisions were made to the coverage as internal reviews found linework errors and polygon tagging errors. This is the first revision to undergo outside review. Reviews_Applied_to_Data: In-house reviews have been completed for the linework and polygon tagging. Reviews were also completed by the Tennessee Division of Geology. Related_Spatial_and_Tabular_Data_Sets: A set of four ASCII text files contain transcriptions of the printed explanations found at the bottom of the four printed 1:250,000 geologic maps. The explanations may be converted to digital form as time and funds allow. Other_References_Cited: Hardeman, W.D., 1966. Geologic Map of Tennessee: Tennessee Department of Environment and Conservation, Division of Geology, 4 maps, scale 1:250,000. Notes: This data set should not be used in applications where legal decisions may arise. Several limitations have influenced the overall accuracy and quality of this data set. Quality and conditon of the source material was acceptable at best. The scribecoats were in poor condition which resulted in a lengthy clean up process for the eastern half of the data set. The scanner used had an acceptable resolution for this project, but a higher resolution would have resulted in better quality linework. The lack of positional registration marks on the source material effected the quality of the geo-referencing. The coverage needs to be checked against the available 1:24,000 geologic quadrangles and adjustments made by a qualified geologist. Unknown The digital data set is as current as the printed maps dated 1966. In work Changes and updates are planned as time and funds allow. Changes may include digital creation of explanations, updates of geologic boundaries and formation designations, and updates to correct possible erorrs in positional accuracy. -90.31191254 -81.64821625 36.67929459 34.98325348 None Tennessee, geology, lithology, fault inlandWaters None State of Tennessee None None None None N/A The positional accuracy of the data set cannot be guaranteed due to the condition of the source material and the lack of positional registration marks. William J. Wolfe U.S. Geological Survey mailing and physical address

640 Grassmere Park Drive, Suite 100

Nashville Tenn. 37211 USA 1-888-275-8747 (615) 837-4799 wjwolfe@usgs.gov 8:00am-4:30pm CST Please contact by email N/A None Unclassified None Windows_NT, 5.0, Intel NT, ARC/INFO version 8.0.2 Hardeman, W.D. 1966 Geology N/A N/A Tennessee Tennessee Division of Geology See Entity_Attribute_Information See explanation Attribute accuracy is described, where present, with each attribute defined in the Entity and Attribute Section. Polygon and chain-node topology present. The data set is not an exact duplication of the printed maps. Some elements of the printed map were not reproducible due to limitations in equipment used, funding, and time. Positional accuracy can not be guaranteed due to limitations in source material, equipment used, and time contraints of qualified personnel. N/A Hardeman, W.D. 1966 250000 Map Unknown None N/A N/A SCANNING THE LINEWORK The Tennessee Division of Geology provided the negatives and/or scribecoats for the west, west-central, east-central, and east map sheets for the 1:250,000 Geologic Map of Tennessee. The negatives for the west and west-cetral sheets were scanned and saved as TIF image files at 400 dpi black and white using a Contex FSS-3012t scanner. Positives were made from the scribecoats for the east-central and east sheets. The positives were scanned using the same system. The resulting images were transferred to a Unix workstation for processing in Arc/Info 7.0. None 1997 None GEO-REFERENCING The original negatives and scribecoats did not have any positional tic marks which could be used for geo-referencing. The 1:250,000 USGS Tennessee state boundary had to be used as a reference. Each of the four scanned images were geo-referenced into the Universal Transverse Mercator Zone 16 coordinate system using the Arc/Info REGISTER command. Because of the lack of positional registration on the source material, positional accuracy cannot be guaranteed. None 1997 None DELINEATION Due to time contraints and personnel shortage, hand delineation of the geologic features was not possible. An automated method of delineation from the scanned data was tested. The images were converted into GRIDs using the Arc/Info IMAGEGRID command. Several attempts at automated delineation were made using the GRIDLINE command. After several variations on command parameters, the resulting linework was acceptable and passed onto the next step. None 1997 None CLEANING The linework resulting from the GRIDLINE command was a good conversion from the raster data, but many problems had to be solved. Because of scanner limitations, some of the closer linework merged together into single lines. These had to be deleted and digitzed by hand. There were many spots where linework had "spider-webbed". This occurred where the linework was close but not close enough to merge and cause the automated delineation to create spurious lines between the actual lines. These extraneous lines were removed as well. After linework errors were corrected, the resulting linework was passed through the SPLINE command in ArcEdit. This smoothed out most of the jagged linework caused by the GRIDLINE command. As a side effect, fault lines were altered where intersected by other linework. Some of these effects were corrected when they were visible on a paper plot while most were left as they were for future correction. After errors were corrected, polygons were built from the linework and then checked for closure. Errors found were corrected and the coverage was rebuilt. This process was repeated for each of the four sheets until all obvious errors were corrected. None 1998 None ATTRIBUTION Once the linework was clean, each line was then tagged as being a nonfault, fault, or metamorphic isograd. During this tagging, more errors were found and corrected. Polygons were attributed with the geologic symbol code found on the printed maps. During this process, more errors were found with unclosed polygons which were fixed and retagged. Each of the four sheets went through this process. Each sheet was then plotted to scale using a custom Arc/Info shadeset designed to mimic the printed shade patterns as closely as possible. This process allowed easier verification of the geologic formation attribution. Any errors in linework, line attribution, and polygon attribution were corrected. None 1998 None MERGING The two sheets for western Tennessee were appended together. The resulting linework at the sheet boundaries had to be cleaned and the map boundaries removed. The polygons were then checked for correct attribution along the map boundary and any errors were corrected. The same process was repeated for the eastern Tennessee sheets. The two resulting coverages where then merged into a single coverage using the same process of removing map boundaries and checking/correcting polygon and line features and attribution. Once all four sheets were merged into a single coverage, all polygons with an area of less than 5,000 square meters were removed. These polygons were impossible to recognize when plotted at scale and, in most cases, were "spider-webbing" errors not found during the inital delineation process. None 1999 None Vector Point 12897 String 28587 GT-polygon composed of chains 12897 0.0000082061451 0.0000082061451 Decimal Degrees North American Datum of 1983 GRS1980 6378206.4 294.98 GEO250K.PAT Polygon attribute table Printed maps Shape Polygon attribute table Printed maps Positive real numbers 2-dimensional element Printed maps AREA Area of poly/region in square coverage units Computed Positive real numbers Area of region in square coverage units GIS software PERIMETER Perimeter of poly/region in coverage units Computed Positive real numbers Perimeter of region in coverage units GIS software GEO250K# Internal feature number Computed Sequential unique positive integer Internal feature number GIS software GEO250K-ID User-assigned feature number User defined Integer User-assigned feature number GIS software GEO Geologic symbol identifier Printed 1:250,000 geologic maps character string Geologic symbol identifier printed 1:250,000 geologic maps Geo250K.AAT Arc attribute table Printed maps Shape Arc attribute table Printed maps Positive real numbers 1-dimensional element Printed maps FNODE# Internal number of from-node Computed Sequential unique positive integer Internal number of from-node GIS software TNODE# Internal number of to-node Computed Sequential unique positive integer Internal number of to-node GIS software LPOLY# Internal number of poly to left of arc Computed Sequential unique positive integer Internal number of poly to left of arc GIS software RPOLY# Internal number of poly to right of arc Computed Sequential unique positive integer Internal number of poly to right of arc GIS software LENGTH Length of arc in coverage units Computed Positive real numbers Length of arc in coverage units GIS software GEO250K# Internal feature number Computed Sequential unique positive integer Internal feature number GIS software GEO250K-ID User-assigned feature number User defined Integer User-assigned feature number GIS software FAULT Type of line Printed 1:250,000 geologic maps 1 - contact, 2 - fault, 3 - metamorphic isograd Type of line Printed 1:250,000 geologic maps The .AAT file contains one user-defined attribute, FAULT. This field defines each line in the dataset as being one of three types. The line is either 1 - a nonfault line, 2 - a fault line, 3 - a metamorphic isograd. Some lines are not visible on the printed maps due to the unknown boundary of geologic formations. These lines were not differentiated in the digital coverage but may be in future revisions. The .PAT file contains one user-defined attribute, GEO. This field is a representation of the geologic symbol or code found on the printed maps. 'NONE' is used where the map was blank and 'WATR' is used in the Western half of Tennessee, where geologic formations were not delineated beyond water boundaries. Not Available U.S. Geological Survey Ask USGS - Water Webserver Team mailing

445 National Center

Reston VA 20192 1-888-275-8747 (1-888-ASK-USGS) http://water.usgs.gov/user_feedback_form.html Although this data set has been used by the U.S. Geological Survey, U.S. Department of the Interior, no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data and related materials. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the U.S. Geological Survey in the use of this data, software, or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Other Microsoft Word 1 http://water.usgs.gov/GIS/dsdl/geo250k.doc Export Full coverage zipped 1 http://water.usgs.gov/GIS/dsdl/geo250k.e00.gz Other Full coverage zipped 1 http://water.usgs.gov/GIS/dsdl/geo250k.sdts.tgz None. This dataset is provided by USGS as a public service. 20041108 U.S. Geological Survey Ask USGS -- Water Webserver Team mailing

445 National Center

Reston VA 20192 1-888-275-8747 (1-888-ASK-USGS) http://answers.usgs.gov/cgi-bin/gsanswers?pemail=h2oteam&subject=GIS+Dataset+geo250k FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998