Metadata: Identification_Information: Citation: Citation_Information: Originator: Tim Wade Publication_Date: 200402 Title: Causes of Forest Fragmentation in the United States – 270 Meter Resolution Geospatial_Data_Presentation_Form: Map Publication_Information: Publication_Place: Reston, VA Publisher: National Atlas of the United States Online_Linkage: Description: Abstract: This map layer is a grid map of the conterminous United States, created from National Land Cover Data (NLCD). The NLCD data was reclassified into four categories: forest, other natural (e.g. grassland, wetland, etc.), human land use (e.g. agriculture, urban, etc.), and nodata (water, ice and snow, and bare rock/sand). A 9 x 9-pixel moving window was then used to generate forest edge measurements for every pixel, regardless of its class. Within each window, the edges of all forest pixels were examined to determine what type of land cover shared each edge. Three new grids were created, one for each edge type (forest-forest, forest-natural, and forest-human). The values in these grids were calculated as the number of edges with the appropriate type in the window divided by the total number of forest edges, regardless of neighbor. These grids represented forest connectivity (forest-forest edges), naturally caused forest fragmentation (forest-natural edges), and human caused forest fragmentation (forest- human edges). In the map, forest connectivity is displayed in green, natural fragmentation in blue, and human fragmentation in red. Yellow indicates areas that are an approximately equal mix of connected forest and human fragmentation, while cyan indicates areas that are an approximately equal mix of connected forest and natural fragmentation. Black represents areas with no forest in the 9 x 9-pixel window; white represents ignored or nodata areas, such as water, ice and snow, and bare rock/sand. The data available through the National Atlas of the United States are in GeoTIFF format. Purpose: Forest fragmentation has been studied extensively and can be quantified in several ways. This map layer is the first to identify sources of forest fragmentation, separating fragmentation into human and natural components. The data may be a useful tool for decision makers in identifying areas for protection or restoration. Areas displayed in yellow represent transition zones between connected forest and human-fragmented forest. Because human land uses tend to expand over time, these areas will be the most likely to experience further degradation. In time, the transition zones may become highly fragmented and new transitional areas will appear deeper in the intact forest. Consequently, the yellow areas in the map may represent excellent opportunities for protection or restoration. Protecting transitional and adjacent areas may limit further expansion or degradation of the transitional areas. Restoration efforts to eliminate or reduce fragmentation may produce larger patches of connected forest. Supplemental_Information: Downloadable data is scaled from 0 to 100 and is meant to be used in analyses. For display purposes, it is recommended that the data be rescaled from 0 to 255 to capture the full spectrum of possible fragmentation combinations. Colors are subdued and yellows and cyans may be missing in the display, using data scaled from 0 to 100. These data are based on National Land Cover Data (NLCD). Information about NLCD is available online at: . For additional information see Vogelmann, J.E., S.M. Howard, L. Yang, C.R. Larson, B.K. Wylie, and N. van Driel. 2001. Completion of the 1990s National land cover data set for the conterminous United States from Landsat Thematic Mapper data and ancillary data sources. Photogrammetric Engineering and Remote Sensing 67: 650-662. The data are stored in three bands, one each for forest connectivity (Pff), human fragmentation (Pfa), and natural fragmentation (Pfn). Values have been scaled from 0 to 100, with -9999 (nodata) where the NLCD identified water, ice and snow, or bare rock/sand (classes 11, 12 and 31). Values of 0 occur where the 9 x 9-pixel window contained no forest pixels or where all forest pixels were surrounded by nodata pixels. A value of 100 indicates a window where all forest pixel edges adjoin only one class. For example, a 100 in the forest connectivity band means all forest pixels in the window are adjacent to other forest pixels or a nodata pixel. It does not necessarily mean that all pixels in the window are forest. To display these data, it is highly recommended that their values be stretched to range from 0 to 255. This will brighten and enhance the contrast in the image. Detailed information on the algorithms used to process the NLCD data to create a global fragmentation map can be found in: Wade, T.G, K.H. Riitters, J.D. Wickham, and K.B. Jones, 2003. Distribution and causes of global forest fragmentation. Conservation Ecology 7(2): 7. [online] URL: . Similar procedures were used to create this map layer. The United States Environmental Protection Agency (EPA), through its Office of Research and Development (ORD), partially funded and collaborated in this work under Interagency Agreement DW12939283-01-0 with the United States Department of Agriculture. It has been subjected to Agency review and approved for publication. The associated world file is included as part of the GeoTIFF. The contents of the world file are: >270.0000 >0.000000 >0.000000 >-270.0000 >-2262865.0000 >1038776.0000 The following projection file can be used when using ESRI's ArcGIS to view the GeoTIFF (any line breaks should be removed): PROJCS["NAD_1983_Lambert_Azimuthal_Equal_Area",GEOGCS ["GCS_Sphere_ARC_INFO",DATUM["D_Sphere_ARC_INFO",SPHEROID ["Sphere_ARC_INFO",6370997.0,0.0]],PRIMEM["Greenwich",0.0], UNIT["Degree",0.0174532925199433]],PROJECTION ["Lambert_Azimuthal_Equal_Area"],PARAMETER["False_Easting",0.0], PARAMETER["False_Northing",0.0],PARAMETER["Central_Meridian", -100.0],PARAMETER["Latitude_Of_Origin",45.0],UNIT["Meter",1.0]] Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 1992 Currentness_Reference: Primary date of source imagery Status: Progress: Complete Maintenance_and_Update_Frequency: Irregular Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -125 East_Bounding_Coordinate: -66 North_Bounding_Coordinate: 50 South_Bounding_Coordinate: 24 Keywords: Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: biota Theme_Keyword: environment Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: Biodiversity Theme_Keyword: Land cover Theme_Keyword: Forest Theme_Keyword: Fragmentation Theme_Keyword: Landscape Place: Place_Keyword_Thesaurus: None Place_Keyword: United States Place_Keyword: USA Place: Place_Keyword_Thesaurus: U.S. Department of Commerce, 1987, Codes for the Identification of the States, the District of Columbia and the Outlying Areas of The United States, and Associated Areas (Federal Information Processing Standard 5-2): Washington, DC, National Institute of Standards and Technology. Place_Keyword: Alabama Place_Keyword: Arizona Place_Keyword: Arkansas Place_Keyword: California Place_Keyword: Colorado Place_Keyword: Connecticut Place_Keyword: Delaware Place_Keyword: District of Columbia Place_Keyword: Florida Place_Keyword: Georgia Place_Keyword: Idaho Place_Keyword: Illinois Place_Keyword: Indiana Place_Keyword: Iowa Place_Keyword: Kansas Place_Keyword: Kentucky Place_Keyword: Louisiana Place_Keyword: Maine Place_Keyword: Maryland Place_Keyword: Massachusetts Place_Keyword: Michigan Place_Keyword: Minnesota Place_Keyword: Mississippi Place_Keyword: Missouri Place_Keyword: Montana Place_Keyword: Nebraska Place_Keyword: Nevada Place_Keyword: New Hampshire Place_Keyword: New Jersey Place_Keyword: New Mexico Place_Keyword: New York Place_Keyword: North Carolina Place_Keyword: North Dakota Place_Keyword: Ohio Place_Keyword: Oklahoma Place_Keyword: Oregon Place_Keyword: Pennsylvania Place_Keyword: Rhode Island Place_Keyword: South Carolina Place_Keyword: South Dakota Place_Keyword: Tennessee Place_Keyword: Texas Place_Keyword: Utah Place_Keyword: Vermont Place_Keyword: Virginia Place_Keyword: Washington Place_Keyword: West Virginia Place_Keyword: Wisconsin Place_Keyword: Wyoming Access_Constraints: None Use_Constraints: None. Acknowledgment of the National Atlas of the United States of America, the U.S. Environmental Protection Agency, the U.S. Forest Service, and (or) the U.S. Geological Survey would be appreciated in products derived from these data. Point_of_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Tim Wade Contact_Organization: U.S. Environmental Protection Agency Contact_Address: Address_Type: Mailing and physical address Address: E243-05 City: Research Triangle Park State_or_Province: NC Postal_Code: 27711 Contact_Voice_Telephone: 919-541-4119 Contact_Electronic_Mail_Address: wade.timothy@epa.gov Data_Set_Credit: This map was derived from the 1992 NLCD. Funding to create the NLCD came from the Multi-Resolution Land Characteristics (MRLC) Consortium . Partners in the MRLC included the U.S. Geological Survey (USGS), U.S. Environmental Protection Agency (EPA), National Oceanic and Atmospheric Administration (NOAA), and U.S. Forest Service (USFS). For additional information see Vogelmann, J.E., T. Sohl, and S.M. Howard, 1998. Regional characterization of land cover using multiple sources of data. Photogrammetric Engineering and Remote Sensing, 64: 45-57. Native_Data_Set_Environment: These data are presently stored in grid format, ESRI Arc/INFO version 8.3 running under Windows. The data available through the National Atlas of the United States are in GeoTIFF format. Cross_Reference: Citation_Information: Originator: Tim Wade Publication_Date: 200402 Title: Causes of Forest Fragmentation in the United States – 540 Meter Resolution Geospatial_Data_Presentation_Form: Map Publication_Information: Publication_Place: Reston, VA Publisher: National Atlas of the United States Online_Linkage: Cross_Reference: Citation_Information: Originator: Tim Wade Publication_Date: 200402 Title: Causes of Forest Fragmentation in the United States – 1 Kilometer Resolution Geospatial_Data_Presentation_Form: Map Publication_Information: Publication_Place: Reston, VA Publisher: National Atlas of the United States Online_Linkage: Cross_Reference: Citation_Information: Originator: Kurt Riitters Publication_Date: 200212 Title: Classification of Forest Fragmentation in North America Geospatial_Data_Presentation_Form: Map Publication_Information: Publication_Place: Reston, VA Publisher: National Atlas of the United States Online_Linkage: Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: Thematic accuracy of the fragmentation data is directly related to the accuracy of the NLCD. An accuracy assessment of the NLCD has been completed and published. For further information see Stehman, S.V., J.D. Wickham, J.H. Smith, and L. Yang. 2003. Thematic accuracy of the 1992 National Land-Cover Data (NLCD) for the eastern United States: statistical methodology and regional results. Remote Sensing of Environment, 86:500-516. Information on the western United States will be published soon as Wickham, J.D., S.V. Stehman, J.H. Smith, and L. Yang. (Accepted pending revision). Thematic accuracy of 1992 National Land-Cover Data (NLCD) for the western United States. Remote Sensing of Environment. The fragmentation values are best interpreted as relative to other places on the same map. Comparisons with other maps prepared from different data sources or at different scales are tenuous. Logical_Consistency_Report: All cell values are in the range [0,100] plus a -9999 value for nodata. Nodata represents water, ice and snow, or bare rock/sand. Completeness_Report: Every cell in the original land cover map potentially has values representing fragmentation and connectivity. Some regions (coastal) may have missing values as a result of reprojecting the fragmentation map to a standard projection and clipping to a mask. Other regions (e.g., islands within large inland water bodies) may have missing values as a result of there being too few non-water pixels in the analysis window to provide a valid value. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: The positional accuracy of the forest fragmentation map is the same as the positional accuracy of the NLCD. Lineage: Source_Information: Source_Citation: Citation_Information: Originator: U.S. Geological Survey Publication_Date: 1998 Title: National Land Cover Dataset 1992 Publication_Information: Publication_Place: Sioux Falls, SD Publisher: USGS, Center for EROS Other_Citation_Details: The procedures used in development of this map layer are described in: Vogelmann, J.E., S.M. Howard, L. Yang, C.R. Larson, B.K. Wylie, N. Van Driel, 2001. Completion of the 1990s National Land Cover Data Set for the Conterminous United States from Landsat Thematic Mapper Data and Ancillary Data Sources. Photogrammetric Engineering and Remote Sensing, 67:650-652. Online_Linkage: Type_of_Source_Media: Online Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 1992 Source_Currentness_Reference: Primary date of source imagery Source_Citation_Abbreviation: NLCD Source_Contribution: Land cover map Source_Information: Source_Citation: Citation_Information: Originator: National Atlas of the United States Publication_Date: 1999 Title: North America Land/Water Mask Publication_Information: Publication_Place: Reston, VA Publisher: National Atlas of the United States Type_of_Source_Media: ftp site Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 1999 Source_Currentness_Reference: Publication date Source_Citation_Abbreviation: GRDMSKI0201 Source_Contribution: Shoreline information Process_Step: Process_Description: Land-cover data (NLCD) were obtained from the Center for EROS in band sequential (bsq) format. Each State plus the District of Columbia were obtained in separate files (Alaska and Hawaii are not included in the NLCD). For each State, a header was created using the NLCD metadata. The State bsq file was then converted to an in-house format using an in-house software tool named BSQ2TVA.C. Each State map was subdivided into four overlapping rectangles using an in-house software tool named SPLITTER.C. The rectangles overlapped to avoid artifacts near image boundaries during subsequent spatial filtering operations. The subdivision was then repeated for each of the four rectangles, to produce a total of 16 rectangles for each State. Because of its small size, the map for the District of Columbia (only) was not subdivided, but instead was processed as one map using the following procedures. The in-house spatial filtering program SPATCONV.C was used to process each of the 16 rectangles. The processing measured the proportion of forest pixel edges that joined forest pixels to forest pixels, to other natural pixels, and to human pixels, within 9 x 9-pixel windows centered on each of the original NLCD pixels. First, the land-cover map was condensed to four classes - forest (NLCD codes 41, 42, 43, 91), other natural (NLCD codes 51, 52, 53, 71, 92), human (NLCD codes 21, 22, 23, 32, 33, 61, 81, 82, 83, 84, 85), and nodata (NLCD codes 11, 12, 31). Next, a connectivity of forest value (Pff) was determined for each forested pixel by calculating the proportion of adjacent pixel pairs that were both forest, given that at least one of a pair was forest, for pixel pairs within a 9 x 9-pixel window centered on the subject pixel. Also, a fragmentation by natural causes value (Pfn) was determined for each forested pixel by calculating proportion of adjacent pixel pairs where one was forest and the second was natural, given that at least one of a pair was forest, for pixel pairs within a 9 x 9-pixel window centered on the subject pixel. Also, a fragmentation by human causes value (Pfa) was determined for each forested pixel by calculating proportion of adjacent pixel pairs where one was forest and the second was human, given that at least one of a pair was forest, for pixel pairs within a 9 x 9-pixel window centered on the subject pixel. "Adjacent pixels" were defined as being in cardinal directions only, and pixel pairs involving nodata pixels were excluded from the calculation. Pff (roughly) estimates the probability that, given a pixel of forest, its neighbor is also forest. Forest connectivity is higher for larger values of Pff. Pfa and Pfn partition into components the non- connectivity of forest, based on human and natural land-cover types. The indices (Pff, Pfa, and Pfn) are continuous variables and range from zero to one. The calculated values were discretized to the range [1,255] and stored at 30-meter spatial resolution. The transformation used to discretize the values was: >D = (C * 254) + 1 >where >D = discretized value in range [1,255] >C = calculated value of Pff, Pfa, or Pfn in range [0,1] The sixteen rectangles of a given index were exported in an in-house format and reassembled into State-level images via an in-house software tool named LUMPER.C, which removed the overlapping parts of the rectangles. The in-house software tool TVA2BSQ.C was then used to convert the format to bsq and the resulting files were imported into Arc/INFO by using the command IMAGEGRID. Two additional steps were completed to reduce the sizes of the maps. The RESAMPLE command (nearest neighbor option) in the Arc/INFO grid module was used to convert each State-level grid to a grid with 270- meter resolution. The MERGE command in the Arc/INFO grid module was used to combine all State-level maps at 270-meter resolution into one map. The final product consisted of three national maps at 270-meter resolution, one for Pff (forest connectivity), one for Pfa (human-caused fragmentation), and one for Pfn (natural fragmentation). The georeferencing did not change as a result of reformatting, exporting, importing, or spatial filtering. Source_Used_Citation_Abbreviation: NLCD Process_Date: 2001 Process_Step: Process_Description: Values for Pff, Pfa and Pfn were rescaled to 0 to 100 so that fragmentation and connectivity can be thought of in percentage terms (Pff + Pfa + Pfn = 100). The exception is when all are equal to 0 which indicates a pixel whose associated window contains no forest or where all forest edges adjoin nodata pixels. Nodata values represent land cover that was ignored (water, ice and snow, and bare rock/sand). The Pfa, Pff and Pfn grids were projected to the Lambert Azimuthal Equal Area projection, using the Arc/INFO command PROJECT. This projection is the standard projection used for image files in the National Atlas of the United States. Nearest neighbor resampling was used, and cell size was maintained at 270 meters. Each of the grids was clipped using the USGS water mask grid (GRDMSKI0201). The clip was performed in Arc/INFO Grid by using the CON function to delete data in the Pfa, Pff and Pfn grids where the mask grid was water. The three grids were combined into a stack using the MAKESTACK command in Arc/INFO Grid. They were exported using GRIDIMAGE in Arc/INFO, using the tif option. Two files were created during the conversion, the TIFF image and a world file (.tfw extension) containing real-world coordinate transformation information. Information in the world file is embedded into the TIFF image to create a GeoTIFF image. Source_Used_Citation_Abbreviation: GRDMSKI0201 Source_Used_Citation_Abbreviation: FRAG1 Process_Date: 2003 Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Raster Raster_Object_Information: Raster_Object_Type: Grid Cell Row_Count: 12800 Column_Count: 19067 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Map_Projection: Map_Projection_Name: Lambert Azimuthal Equal Area Lambert_Azimuthal_Equal_Area: Longitude_of_Projection_Center: -100.00 Latitude_of_Projection_Center: 45.00 False_Easting: 0.0 False_Northing: 0.0 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: Row and column Coordinate_Representation: Abscissa_Resolution: 270 Ordinate_Resolution: 270 Planar_Distance_Units: Meters Geodetic_Model: Horizontal_Datum_Name: None Ellipsoid_Name: Sphere Semi-major_Axis: 6370997.0 Denominator_of_Flattening_Ratio: 1.0 Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: Forest fragmentation grid cell Entity_Type_Definition: Any of the data elements in the forest fragmentation file. Entity_Type_Definition_Source: National Atlas of the United States Attribute: Attribute_Label: Forest fragmentation grid cell value Attribute_Definition: In bands 1 (human fragmentation) and 3 (natural fragmentation), lower values represent smaller amounts of fragmentation. In band 2 (forest connectivity), lower values represent less-connected forest. A value of 0 in band 2 means there is no forest in the pixel’s associated window or that all forest pixels are completely surrounded by nodata. Attribute_Definition_Source: National Atlas of the United States Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0 Range_Domain_Maximum: 100 Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: -9999 Enumerated_Domain_Value_Definition: Nodata pixel, containing water, ice and snow, or bare rock/sand. Enumerated_Domain_Value_Definition_Source: National Atlas of the United States Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: Earth Science Information Center, U.S. Geological Survey Contact_Address: Address_Type: Mailing address Address: 507 National Center City: Reston State_or_Province: VA Postal_Code: 20192 Contact_Voice_Telephone: 1-888-ASK-USGS (1-888-275-8747) Contact_Voice_Telephone: 703-648-5920 Contact_Instructions: In addition to the address above there are other ESIC offices throughout the country. A full list of these offices is at . Distribution_Liability: Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made by the U.S. Geological Survey regarding the utility of the data on any other system, nor shall the act of distribution constitute any such warranty. No responsibility is assumed by the U.S. Geological Survey, U.S. Environmental Protection Agency, or U.S. Forest Service in the use of these data. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: TIFF Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: Fees: There is no charge for the map layer. Metadata_Reference_Information: Metadata_Date: 20060420 Metadata_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Peg Rawson Contact_Organization: National Atlas of the United States Contact_Address: Address_Type: Mailing address Address: 12201 Sunrise Valley Drive Address: MS-561 City: Reston State_or_Province: VA Postal_Code: 20192 Contact_Voice_Telephone: 703-648-4183 Contact_Electronic_Mail_Address: atlasmail@usgs.gov 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