Identification_Information: Citation: Citation_Information: Originator: Kurt Riitters, U.S. Forest Service Publication_Date: 2000 Title: WVLC.SUMD27 - West Virginia Land Cover Contagion at 66 hectare Scale Edition: 2 Geospatial_Data_Presentation_Form: Map Publication_Information: Publication_Place: Research Triangle Park, NC Publisher: U.S. Forest Service Online_Linkage: Description: Abstract: This dataset is a grid map for West Virginia at 30 meter Resolution. Each pixel value represents an index of land cover contagion ("tendency to form clumps") for the surrounding 65.61 ha.(27x27 pixel) analysis window. The dataset was created by applying a spatial filter to a published map of land cover from the Multi-Resolution Land Characteristics (MRLC) Consortium. The spatial filter computed an index of contagion from the attribute adjacency table of land cover types. The [0,1] continuous index was discretized, and a byte representation [1,255] was stored at the center location (i.e., at the center pixel) in a new map. Each pixel in the new map is an index of overall contagion, for the surrounding 65.61 ha window, for the corresponding pixel in the original land cover map. Purpose: These data were created as part of a national analysis of land cover pattern. A series of derived maps (different indices, different window sizes) is available. They are proposed for consideration by landscape analysts, as independent variables (e.g., covariates, stratification rules), and as "context" information for finer-scale investigations, for example field plots. Caveats include: Maps in this series are naturally correlated since all came from one map. No warranty or claim is made of the utility of this map for any particular purpose, this is considered to be a research dataset. The contagion map portrays relative contagion, at one scale, considering only the MRLC land cover types. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 1988 Ending_Date: 1993 Currentness_Reference: Dates of satellite imagery. Status: Progress: Complete Maintenance_and_Update_Frequency: Irregular Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -84 East_Bounding_Coordinate: -76 North_Bounding_Coordinate: 41 South_Bounding_Coordinate: 36 Keywords: Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: pattern Theme_Keyword: landcover Theme_Keyword: landscape Theme_Keyword: contagion Place: Place_Keyword_Thesaurus: None Place_Keyword: WV Place_Keyword: United States Place_Keyword: West Virginia Access_Constraints: None Use_Constraints: None. Acknowlegement of the U.S. Forest Service would be appreciated in products derived from these data. To support further development of the database, please send a postcard or reprint. Point_of_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Kurt Riitters Contact_Organization: U.S. Forest Service Contact_Address: Address_Type: mailing address Address: Box 12254 3041 Cornwallis Road City: Research Triangle Park State_or_Province: NC Postal_Code: 27709 Contact_Voice_Telephone: 919-549-4015 Contact_Electronic_Mail_Address: kriitters@fs.fed.us Data_Set_Credit: The basic data from which this map was derived were provided by the Multi-Resolution Land Characteristics Consortium, hosted by the EROS Data Center. Native_Data_Set_Environment: These data are stored as a binary image in band-sequential (bsq) format, row-major order, where each byte is one index value. The image is compressed by using the unix compress utility. Cross_Reference: Citation_Information: Originator: Riitters, K.H., O'Neill, R.V., and Jones, K. B. Publication_Date: 1997 Title: Assessing habitat suitability at multiple scales: a landscape-level approach Series_Information: Series_Name: Biological Conservation Issue_Identification: Volume 81, pages 191-202. Other_Citation_Details: Illustration of computer algorithms and an application. Cross_Reference: Citation_Information: Originator: Wickham, J.D., and Riitters, K.H. Publication_Date: 1995 Title: Sensitivity of landscape metrics to pixel size. Series_Information: Series_Name: International Journal of Remote Sensing Issue_Identification: Volume 16, pages 3585-3594. Other_Citation_Details: Definition of land cover contagion index. Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: The contagion index is based on a proportion derived from the attribute adjacency table of MRLC land cover types (see: Process_Step sections). A statistical rule of thumb is that 50 observations are needed to estimate a proportion. The 27x27 pixel analysis window has up to 1404 defined adjacencies (only those involving no "missing" pixels are used in the calculation). This index is one of several which could have been used instead, and standard textbooks discuss relative strengths and weaknesses. Like other indices, this index is best interpreted as a relative value, in comparison to other pixels on the same map. Comparisons with other maps prepared from different data sources or at different scale are tenuous. Logical_Consistency_Report: All cell values are in the range [0,255]. A missing value code (0), was assigned to water or ice land cover types (on the MRLC land cover map), or which were outside the regional boundary (the extent of the MRLC land cover map). Completeness_Report: Every non-null cell in the original land cover map has either a non-zero byte value representing the index, or a missing data value. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: The positional accuracy of the derived map is the same as the positional accuracy of the input map. Lineage: Source_Information: Source_Citation: Citation_Information: Originator: U.S. Geological Survey EROS Data Center Publication_Date: 2000 Title: National Land Cover Data West Virginia Version 03-20-00 Type_of_Source_Media: online Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 1988 Ending_Date: 1993 Source_Currentness_Reference: Dates of satellite imagery. Source_Citation_Abbreviation: MRLC Source_Contribution: Land cover map Process_Step: Process_Description: Derivation of land cover contagion (Wickham and Riitters 1995) from land cover: Land cover data (MRLC) was obtained from EROS Data Center in binary format. The bsq image was subdivided into sixteen (16) overlapping rectangles using an in-house software tool named SPLITTER.C. The rectangles overlapped to avoid artifacts near image boundaries during the spatial filtering operations. Each of the rectangles was then processed via spatial filtering to estimate the index as described below. The spatial filtering program is an in-house software tool named SPATCONV.C (Riitters et al. 1997) After spatial filtering, a map of index values was constructed by reassembling the 16 rectangles into a single image (via an in-house software tool named LUMPER.C, which removed the overlapping parts of rectangles). The "header file" information for the derived map is as follows. This information is needed for some image import filters. Ulxmap and Ulymap refer to the center of the upper-left pixel. nrows 13240 ncols 13265 nbands 1 nbits 8 layout bsq skipbytes 0 ulxmap 1154670.000000 ulymap 2064600.000000 xdim 30.000000 ydim 30.000000 Spatial filtering proceeded as follows. The following land cover classes appear in the MRLC map. 11: open water (missing) 12: perennial ice/snow (missing) 21: low intensity developed 22: high intensity residential 23: high intensity commercial/industrial 31: bare rock/sand/clay 32: quarries/strip mines/gravel pits 33: transitional barren 41: deciduous forest 42: evergreen forest 43: mixed forest 51: deciduous shrubland 52: evergreen shrubland 53: mixed shrubland 61: planted/cultivated (orchards,vineyards, groves) 71: grassland/herbaceous 81: hay/pasture 82: row crops 83: small grains 84: bare soil 85: other grass (lawns, city parks, golf courses) 91: woody wetland 92: emergent herbaceous wetland A 27x27 pixel quadrat was centered on each pixel of the original land cover map. An attribute adjacency table was then tabulated, considering only pixel pairs in cardinal directions (i.e., four neighbors per pixel), and counting each pixel pair once. The contagion index was then computed from the attribute adjacency table by first dividing each cell in the table by the total number of pixel pairs, then summing the main diagonal elements. This yields a value of 0 when, for all land cover types, there are no pairs of adjacent pixels which have the same cover type. The maximum value of 1 is obtained when all pixels are adjacent in all cardinal directions to other pixels of the same type. Thus, the range is from zero (low contagion) to one (high contagion). If the center pixel was "missing" in the land cover map, then the index was assigned a "missing" value. Note that the index is defined for all other land cover types. The calculated values were discretized to the range [1,255] and stored at 30-meter spatial resolution. Thus, a pixel value in the new map represents the index for the surrounding 27x27 pixel window in the original land cover map. The transformation used to discretize the values was: D = ( C * 254 ) + 1 where D = discretized value in range [1,255] C = calculated value in range [0,1] If needed, the original calculated values can be approximated by applying the backtransformation: C = ( D - 1 ) / 254 The backtransformed values will be in steps of size approximately 0.00394 as a result of the discretization process. Source_Used_Citation_Abbreviation: MRLC Source_Produced_Citation_Abbreviation: WVLC.SUMD27 Process_Date: 1999 Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Raster Raster_Object_Information: Raster_Object_Type: Grid Cell Row_Count: 13240 Column_Count: 13265 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Map_Projection: Map_Projection_Name: Albers Conical Equal Area Albers_Conical_Equal_Area: Standard_Parallel: 29 30 0 Standard_Parallel: 45 30 0 Longitude_of_Central_Meridian: -96 0 0 Latitude_of_Projection_Origin: 23 0 0 False_Easting: 0.0 False_Northing: 0.0 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: Row and column Coordinate_Representation: Abscissa_Resolution: 30 Ordinate_Resolution: 30 Planar_Distance_Units: meters Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: WVLC.SUMD27 grid cell. Entity_Type_Definition: Any of the data elements. Entity_Type_Definition_Source: U.S. Forest Service Attribute: Attribute_Label: Grid cell value. Attribute_Definition: Byte value representation of land cover contagion index. Attribute_Definition_Source: U.S. Forest Service Attribute_Domain_Values: Range_Domain: Range_Domain_Maximum: 255 (integer) Range_Domain_Minimum: 0 (integer) Distribution_Information: Distributor: Contact_Information: Contact_Person_Primary: Contact_Person: Kurt Riitters Contact_Organization: U.S. Forest Service Contact_Address: Address_Type: mailing address Address: Box 12254 3041 Cornwallis Road City: Research Triangle Park State_or_Province: NC Postal_Code: 27709 Contact_Voice_Telephone: 919-549-4015 Contact_Electronic_Mail_Address: kriitters@fs.fed.us Distribution_Liability: Although these data have been processed successfully on a computer system at the U.S. Forest Service, no warranty expressed or implied is made by the USFS regarding the utility of the data on any other system, nor shall the act of distribution constitute any such warranty. Metadata_Reference_Information: Metadata_Date: 20000830 Metadata_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Kurt Riitters Contact_Organization: U.S. Forest Service Contact_Address: Address_Type: mailing address Address: Box 12254 3041 Cornwallis Road City: Research Triangle Park State_or_Province: NC Postal_Code: 27709 Contact_Voice_Telephone: 919-549-4015 Contact_Electronic_Mail_Address: kriitters@fs.fed.us Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998 Metadata_Security_Information: Metadata_Security_Classification_System: None Metadata_Security_Classification: Unclassified Metadata_Security_Handling_Description: None