Identification_Information: Citation: Citation_Information: Originator: United States Geological Survey (USGS) Central Region Energy Resources Team. Publication_Date: 19990930 Title: Dkovb.shp (Decker overburden) Geospatial_Data_Presentation_Form: map Publication_Information: Publication_Place: Denver, CO Publisher: USGS Central Region Energy Resources Team Description: Abstract: This ArcView shapefile contains a representation of thickness of overburden above the Anderson-Canyon coal zone in the Decker coalfield, Powder River Basin, Montana. This theme was created specifically for the National Coal Resources Assessment in the Northern Rocky Mountains and Great Plains Region. Purpose: The Nation's coal resources are being assessed by the USGS. This assessment identifies and characterizes the coal beds and coal zones that will provide the bulk of the Nation's coal-derived energy during the next few decades. This assessment is different from previous USGS assessments because digital files and databases are being collected and stored in standardized formats, and being analyzed using a Geographic Information System (GIS). Supplemental_Information: The overburden thickness map theme represents a digital polygon coverage of the overburden isopach (thickness) map for the Anderson-Canyon coal zone. The overburden isopach map represents the thickness of rock overlying the top of the Anderson-Canyon coal zone. The extent of the overburden isopach map is constrained by the boundaries of the Crow and Northern Cheyenne Indian Reservations, the Montana state line, and the outcrop (or clinker contact) of the Anderson coal bed, which defines the top of the Anderson-Canyon coal zone. A caveat to Anderson-Canyon coal zone overburden relates to the area lying between the outcrops (or clinker contacts) of the Anderson and Canyon (or lower Canyon) coal beds, which define the top and base of the zone, respectively. Here the coal zone is exposed, and the area technically falls within a category of no overburden. For this reason, this area is defined as "exposed coal zone" in the overburden thickness coverage. In addition, because rocks (including coal beds) in the Anderson-Canyon coal zone may extend from tens to hundreds of feet stratigraphically below the top of the coal zone (Anderson coal bed), the overburden as depicted in the coverage represents a minimum overburden thickness. The overburden interpretations were derived by first developing a grid representing the top of the Anderson-Canyon coal zone (including faults) using a commercial gridding and contouring software package (EarthVision; Dynamic Graphics, Inc.). This grid, which was calculated using a grid spacing of 200 x 200 meters, was then subtracted from a composite Digital Elevation Model (DEM) grid of topographic elevation for the entire coal field, resulting in a grid of thickness values that could then be contoured as overburden thickness isopachs. Multiple 2 arc-second DEMs with a resolution of approximately 60 meters were merged using the 'mosaic' command in ARC/INFO to create the composite DEM grid used in the overburden calculations. The overburden isopach map was then converted to a contour output file in EarthVision, and subsequently converted into a digital polygon coverage by using a combination of programs ('ISMARC' and 'CONVERT-ISM.AML') furnished to the U.S. Geological Survey by the Illinois State Geological Survey. This overburden isopach coverage was then generalized using a weed tolerance of 30 meters to reduce file size. The generalized cover was then converted to a shapefile for incorporation as a theme in the ARCVIEW project. The overburden thickness categories included in the theme (for example, 0 - 100 ft, 100 - 200 ft, etc.) are consistent with overburden thickness categories used in the tabulation of total coal resources. Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 19980000 Currentness_Reference: Publication Date Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -107.0209 East_Bounding_Coordinate: -105.8692 North_Bounding_Coordinate: 45.3536 South_Bounding_Coordinate: 44.9932 Keywords: Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: Anderson-Canyon coal zone Theme_Keyword: Overburden thickness Place: Place_Keyword_Thesaurus: None Place_Keyword: Montana Place_Keyword: Rosebud County Place_Keyword: Powder River County Place_Keyword: Big Horn County Place_Keyword: Powder River Basin Place_Keyword: Decker coalfield Access_Constraints: None Use_Constraints: None Point_of_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: USGS Central Region Energy Resources Team Contact_Person: Steve Roberts Contact_Address: Address_Type: mailing address Address: Box 25046 MS 939 Denver Federal Center City: Denver State_or_Province: CO Postal_Code: 80225-0046 Contact_Voice_Telephone: 303.236.7788 Native_Data_Set_Environment: ArcView version 3.0 ARC/INFO 7.1.2 SUNOS, 5.6, SUN4U UNIX Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: No part of this data was checked for field accuracy. Logical_Consistency_Report: Polygon features present Completeness_Report: Data is limited to overburden above the Anderson-Canyon coal zone in the Decker coalfield. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: Limited to software coordinate precision of geographic coordinates Lineage: Source_Information: Source_Citation: Citation_Information: Originator: USGS Central Region Energy Resources Team Publication_Date: Unknown Publication_Time: Unknown Title: Northern Rocky Mountain and Great Plains Fort Union Stratifact Database. Geospatial_Data_Presentation_Form: map Type_of_Source_Media: Digital Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: Unknown Source_Currentness_Reference: Publication Date Source_Citation_Abbreviation: None Source_Contribution: This was the only source used for this shapefile. Process_Step: Process_Description: The overburden interpretations were derived by first developing a grid representing the top of the Anderson-Canyon coal zone (including faults) using a commercial gridding and contouring software package (EarthVision; Dynamic Graphics, Inc.). This grid, which was calculated using a grid spacing of 200 x 200 meters, was then subtracted from a composite Digital Elevation Model (DEM) grid of topographic elevation for the entire coal field, resulting in a grid of thickness values that could then be contoured as overburden isopachs. Multiple 2 arc-second DEMs with a resolution of approximately 60 meters were merged using the 'mosaic' command in ARC/INFO to create the composite DEM grid used in the overburden calculations. The overburden isopach map was then converted to a contour output file in EarthVision, and subsequently converted into a digital polygon coverage by using a combination of programs ('ISMARC' and 'CONVERT-ISM.AML') furnished to the U.S. Geological Survey by the Illinois State Geological Survey. This overburden isopach coverage was then generalized using a weed tolerance of 30 meters to reduce file size. The generalized cover was then converted to a shapefile for incorporation as a theme in the ARCVIEW project. The overburden thickness categories included in the theme (for example, 0 - 100 ft, 100 - 200 ft, etc.) are consistent with overburden thickness categories used in the tabulation of total coal resources. Process_Date: Unknown Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: USGS Central Region Energy Resources Team Contact_Person: Steve Roberts Contact_Address: Address_Type: mailing address Address: Box 25046 MS 939 Denver Federal Center City: Denver State_or_Province: CO Postal_Code: 80225-0046 Contact_Voice_Telephone: 303.236.7788 Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Vector Point_and_Vector_Object_Information: SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: GT-polygon composed of chains Point_and_Vector_Object_Count: 474 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Geographic: Latitude_Resolution: .0001 Longitude_Resolution: .0001 Geographic_Coordinate_Units: Decimal degrees Geodetic_Model: Horizontal_Datum_Name: North American Datum 1927 Ellipsoid_Name: Clarke 1866 Semi-major_Axis: 6378206.4 Denominator_of_Flattening_Ratio: 294.98 Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: dkovb.dbf Entity_Type_Definition: Shapefile Attribute Table Entity_Type_Definition_Source: None Attribute: Attribute_Label: Areab Attribute_Definition: Area of polygon Attribute_Definition_Source: Software computed Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0.0000 Range_Domain_Maximum: 983205.0000 Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: USGS Central Region Energy Resources Team Contact_Address: Address_Type: mailing address Address: Box 25046 MS 939 Denver Federal Center City: Denver State_or_Province: CO Postal_Code: 80225-0046 Contact_Voice_Telephone: 303.236.1647 Distribution_Liability: The US Geological Survey provides these geographic data "as is." The USGS makes no guarantee or warranty concerning the accuracy of information contained in this geographic data. The USGS further makes no warranties, either expressed or implied as to any other matter whatsoever, including, without limitation, the condition of the product, or its fitness for any particular purpose. The burden for determining fitness for use lies entirely with the user. Although these data have been processed successfully on USGS computers, no warranty, expressed or implied, is made by the USGS regarding the use of these data on any other system, nor does the fact of distribution constitute or imply any such warranty. In no event shall the USGS have any liability whatsoever for payment of any consequential, incidental, indirect, special, or tort damages of any kind, including, but not limited to, any loss of profits arising out of use of or reliance on the geographic data or arising out of the delivery, installation, operation, or support by the USGS. Metadata_Reference_Information: Metadata_Date: 19980000 Metadata_Review_Date: 19990000 Metadata_Future_Review_Date: 19990000 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: USGS Central Region Energy Resources Team Contact_Person: Steve Roberts Contact_Address: Address_Type: mailing address Address: Box 25046 MS 939 Denver Federal Center City: Denver State_or_Province: CO Postal_Code: 80225-0046 Country: USA Contact_Voice_Telephone: 303.236.7788 Metadata_Standard_Name: FGDC CSDGM Metadata_Standard_Version: 19940608