Identification_Information:
	Citation:
		Citation_Information:
			Originator: United States Geological Survey (USGS) Central Region Resources Team
			Publication_Date: 19990930
			Title: Rsovb.shp (Overbuden in the Rosebud-Robinson Coal Zone)
			Publication_Information:
				Publication_Place: Denver
				Publisher: USGS Central Region Energy Resources Team
	Description:
		Abstract:
			This ArcView shapefile contains a polygon representation
			of the overburden to the base of the Rosebud-Robinson 
			coal zone, Colstrip 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 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 Rosebud-Robinson coal zone.
			In this theme, the overburden isopach map represents
			the thickness of rock overlying the base of the
			Rosebud-Robinson coal zone.  The extent of the
			overburden isopach map is constrained by the boundaries
			of the Crow and Northern Cheyenne Indian Reservations,
			and the outcrop traces (or clinker contacts) of the 
			Rosebud and Robinson (or lower Robinson) coal beds.   
			Because the overburden isopach represents the thickness 
			of rock lying above the base of the Rosebud-Robinson 
			coal zone, the map defines the maximum overburden for 
			the coal zone.
			The overburden in this case also includes all coal beds 
			and interburden in the Rosebud-Robinson coal zone.
	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: -107.2459
			East_Bounding_Coordinate: -106.4404
			North_Bounding_Coordinate: 45.9820
			South_Bounding_Coordinate: 45.6728
	Keywords:
		Theme:
			Theme_Keyword_Thesaurus: None
			Theme_Keyword: Rosebud-Robinson coal zone
			Theme_Keyword: Overburden
		Place:
			Place_Keyword_Thesaurus: None
			Place_Keyword: Rosebud County
			Place_Keyword: Treasure County
			Place_Keyword: Big Horn County
			Place_Keyword: Montana
			Place_Keyword: Colstrip Coalfield
			Place_Keyword: Northern Rocky Mountains and Great Plains
	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
				Country: USA
			Contact_Voice_Telephone: 303.236.7788
	Native_Data_Set_Environment:
		Sun0S, 5.51 sun4d Unix
		ArcView version 3.0
		ARC/INFO version 7.1.2
Data_Quality_Information:
	Attribute_Accuracy:
		Attribute_Accuracy_Report: No tests were performed
	Logical_Consistency_Report: Polygon features present
	Completeness_Report:
		Overburden is limited to the Rosebud-Robinson coal zone 
		in the Colstrip coalfield, Montana
	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 Resource (Tertiary 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: Ground Condition
			Source_Citation_Abbreviation: None
			Source_Contribution:
				Source provided all information for the maximum 
				overburden above the base of the Rosebud-Robinson 
				coal zone, Colstrip coalfield, Montana
		Process_Step:
			Process_Description:
				The overburden interpretations were derived by first
				developing a grid representing the base of the
				Rosebud-Robinson coal zone (including faults) using a
				commercial gridding and contouring software package
				(EarthVision; Dynamic Graphics, Inc.); the calculated grid
				spacing was 200 x 200 meters.  This grid 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
				DEMs were required to build the composite DEM for the
				Colstrip coal field.  Within the Lame Deer 30 x 60'
				quadrangle (eastern and central parts of the coal field), 2
				arc-second DEMs with a resolution of approximately 60
				meters were used.  In contrast, the only DEM available for 
				the western part of the Colstrip coal field (Hardin 30 x 60' 
				quadrangle) was a 3 arc-second DEM with a resolution of 
				about 90 meters.  The 3 arc-second DEM was resampled
				to correspond to the higher resolution of the 2 arc-second
				DEMs, and all DEMs were subsequently merged using the
				'mosaic' command in ARC/INFO to create a composite
				DEM for 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: 19980000
			Process_Contact:
				Contact_Information:
					Contact_Person_Primary:
						Contact_Person: Steve Roberts
						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
						Country: USA
					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: 445
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: rsovb.dbf
			Entity_Type_Definition: Shapefile Attribute Table
			Entity_Type_Definition_Source: None
		Attribute:
			Attribute_Label: Area
			Attribute_Definition: Area of polygon
			Attribute_Definition_Source: Software computed
			Attribute_Domain_Values:
				Range_Domain:
					Range_Domain_Minimum: 0.00000
					Range_Domain_Maximum: 100834800.00000
		Attribute:
			Attribute_Label: Perimeter
			Attribute_Definition: Perimeter of polygon
			Attribute_Definition_Source: Software computed
			Attribute_Domain_Values:
				Range_Domain:
					Range_Domain_Minimum: 0.00000
					Range_Domain_Maximum: 462965.30000
		Attribute:
			Attribute_Label: Overburden
			Attribute_Definition: Overburden thickness in ft.
			Attribute_Definition_Source: User Defined
			Attribute_Domain_Values:
				Unrepresentable_Domain: Character field
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
				Country: USA
			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: 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