Identification_Information: Citation: Citation_Information: Originator: Kurt Riitters Publication_Date: 200212 Title: Land Cover Diversity Edition: 3 Geospatial_Data_Presentation_Form: Map Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Online_Linkage: Description: Abstract: This data set is an Arc/INFO grid map of North America, excluding Hawaii and including the Caribbean and most of Mexico, that portrays at 1 sq. km resolution an index of land cover diversity calculated at 729 sq. km. scale. The data set was created by applying a spatial filter to a published map of seasonal land cover regions (Loveland et al. 1991) known as NASLCR1_2L which was obtained from the USGS EROS Data Center Distributed Active Archive Center (DAAC). The spatial filter computed Simpson's (1949) index of land cover diversity within 729 sq. km. (27 x 27 pixels) windows from the proportions of different land cover types within a window. The [0,1] continuous index was discretized, and a byte representation (range: [1,245], with zero reserved for missing values) of the index value was stored at the center location in each window. The resulting surface map was projected to a standard projection, and clipped to shorelines defined by the STATP075 shoreline map (USGS). The data available through the National Atlas of the United States are in GeoTIFF format. This is a revised version of the May 2002 data set, with a corrected shoreline for Greenland. Purpose: These data were originally created as part of a global analysis of land cover diversity and pattern based on digital land cover maps derived from remote sensing (AVHRR) and produced by the Global Land Cover Characteristics project. The land cover diversity map portrays relative diversity, considering both natural and anthropogenic land cover types, as a first step towards quantifying biodiversity at landscape-scale levels of biological organization. No responsibility is assumed by the U.S. Geological Survey in the use of these data. Supplemental_Information: In the online, interactive National Atlas of the United States, these data are grouped into 6 classes for display purposes. The display image was created by using the Arc/INFO GRID command SLICE. The resultant grid was converted into a TIFF file for display purposes only. The following lookup table describes the diversity classes in the display TIFF image: >Diversity index value Color RGB values >------------------------------------------------------------- >0 Light Blue 132 193 255 >1-61 Yellow 254 248 156 >62-96 Light Orange 253 196 108 >97-128 Dark Orange 251 126 88 >129-160 Red 243 71 71 >161-191 Light Brown 164 113 72 >192-245 Dark Brown 123 93 62 >255 (unlabeled land area) Gray 129 159 170 > For further information about the Land Cover Characterization Program of the U.S. Geological Survey, please see . Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 1992 Ending_Date: 1993 Currentness_Reference: Dates of satellite imagery. Status: Progress: Complete Maintenance_and_Update_Frequency: Irregular Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: 166 East_Bounding_Coordinate: -4 North_Bounding_Coordinate: 83 South_Bounding_Coordinate: 15 Keywords: Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: Biodiversity Theme_Keyword: Land cover Theme_Keyword: Land cover diversity Theme_Keyword: United States Place: Place_Keyword_Thesaurus: None Place_Keyword: United States Place_Keyword: USA Place_Keyword: Canada Place_Keyword: Mexico Place_Keyword: North America Place_Keyword: Cuba Place_Keyword: Caribbean Place_Keyword: Puerto Rico Place_Keyword: Virgin Islands 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 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 would be appreciated in products derived from these data. Point_of_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Kurt Riitters Contact_Organization: U.S. Forest Service, Southern Research Station Contact_Address: Address_Type: Mailing and physical address Address: 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 USGS, EROS Data Center, Global Land Cover Characteristics Project. Native_Data_Set_Environment: These data are presently stored in grid format, ESRI Arc/INFO version 7.1.1 running under Solaris 2.5.1, workspace size approximately 20MB. The data are also available in ARC EXPORT format, produced by Arc/INFO version 7.1.1 running under Solaris 2.5.1, file size 20,686,335 bytes (compressed). Compression is via standard UNIX COMPRESS running under Solaris 2.5.1. The data available through the National Atlas of the United States are in GeoTIFF format. Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: The Simpson index is based on the proportions of different land cover types within a defined analysis window. A statistical rule of thumb is that 50 observations are needed to accurately estimate a proportion. The analysis window was 27x27 pixels in size, or 729 pixels total, which exceeds the rule of thumb value of 50 needed to estimate a proportion. Simpson's index is just one of many which could have been used to quantify 'diversity'; for a discussion of the relative strengths and weaknesses of various indices, please consult a standard textbook on quantitative ecology. In comparison to other diversity indices, Simpson's index tends to be more sensitive to changes in abundant land cover types and less sensitive to changes in rare cover types, and therefore less sensitive to isolated label errors (mis-classification) on the land cover map. Like other indices, Simpson's 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]. Zero represents ocean or other water, and 255 represents unlabeled land area. Completeness_Report: Every cell identified as land surface in the original land cover map has a non-zero value representing the land cover diversity index. Some coastal regions may have missing values as a result of reprojecting the diversity map to a standard projection and clipping to a mask. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: The positional accuracy of the land cover diversity map is the same as the positional accuracy of the land cover map from which the diversity map was derived. Lineage: Source_Information: Source_Citation: Citation_Information: Originator: U.S. Geological Survey Publication_Date: 1998 Title: GLCC map of seasonal land cover regions for North America, version 1.2L Publication_Information: Publication_Place: Sioux Falls, SD Publisher: EROS Data Center Other_Citation_Details: The procedures used in development of this map are described in Loveland, T.R., Merchant, J.W., Ohlen, D.O., Brown, J.F., 1991. Development of a Land-Cover Characteristics Database for the Conterminous U.S., Photogrammetric Engineering and Remote Sensing 57:1453-1463. Type_of_Source_Media: Online Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 1992 Ending_Date: 1993 Source_Currentness_Reference: Dates of satellite imagery. Source_Citation_Abbreviation: NA_SLCR Source_Contribution: Land cover map (Seasonal Land Cover Regions) Source_Information: Source_Citation: Citation_Information: Originator: U.S. Geological Survey Publication_Date: 1997 Title: 1:7,500,000-scale State Boundaries Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Type_of_Source_Media: ftp site Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 1972 Ending_Date: 1996 Source_Currentness_Reference: Ground condition. Source_Citation_Abbreviation: STATP075 Source_Contribution: Shoreline information Source_Information: Source_Citation: Citation_Information: Originator: Simpson, E.H. Publication_Date: 19490430 Title: Measurement of diversity. Larger_Work_Citation: Citation_Information: Originator: Macmillan and Co., Ltd. Publication_Date: 19490430 Title: Nature Edition: Volume 163, No. 4148 Other_Citation_Details: page 688 Type_of_Source_Media: Journal article Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 1949 Source_Currentness_Reference: Publication date. Source_Citation_Abbreviation: Nature1949 Source_Contribution: Description of diversity index measure Source_Information: Source_Citation: Citation_Information: Originator: Kurt Riitters Publication_Date: 1998 Title: U.S. Diversity map Publication_Information: Publication_Place: Reston Publisher: U.S. Geological Survey Type_of_Source_Media: Internal file Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 1998 Source_Currentness_Reference: Publication date Source_Citation_Abbreviation: SLDIV27_A Source_Contribution: Source file for diversity image Source_Information: Source_Citation: Citation_Information: Originator: Kurt Riitters Publication_Date: 1998 Title: U.S. Diversity map exchange file Publication_Information: Publication_Place: Reston Publisher: U.S. Geological Survey Type_of_Source_Media: Internal file Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 1998 Source_Currentness_Reference: Publication date Source_Citation_Abbreviation: LCD729K.E00 Source_Contribution: Diversity image exchange file Source_Information: Source_Citation: Citation_Information: Originator: Kurt Riitters Publication_Date: 199905 Title: Land Cover Diversity Edition: 1 Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Type_of_Source_Media: online Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 1992 Ending_Date: 1993 Source_Currentness_Reference: Dates of satellite imagery. Source_Citation_Abbreviation: LANDDIV_IMAGE99 Source_Contribution: Land Cover Diversity TIFF image. Source_Information: Source_Citation: Citation_Information: Originator: Kurt Riitters Publication_Date: 200205 Title: Land Cover Diversity Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Type_of_Source_Media: Online Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 1992 Ending_Date: 1993 Source_Currentness_Reference: Dates of satellite imagery. Source_Citation_Abbreviation: LANDDIV_IMAGE200205 Source_Contribution: Land Cover Diversity TIFF image. Source_Information: Source_Citation: Citation_Information: Originator: National Imagery and Mapping Agency Publication_Date: 1990 Title: World Vector Shoreline Publication_Information: Publication_Place: Bethesda, MD Publisher: National Imagery and Mapping Agency Online_Linkage: Type_of_Source_Media: Online Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 1990 Source_Currentness_Reference: Publication date Source_Citation_Abbreviation: WVS Source_Contribution: Shoreline information. Process_Step: Process_Description: Derivation of land cover diversity from land cover: Land cover data (NA_SLCR) was obtained from EROS Data Center in band sequential (bsq) format. The header was created using metadata for NA_SLCR, and brought into Arc/INFO using the IMAGEGRID command. The land cover data was exported to ASCII format using the Arc/INFO command GRIDASCII, and the format was converted to an in-house format using an in-house software tool named ASC2TVA.C. The map was subdivided into four (4) 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. The in-house spatial filtering program SPATCONV.C was used to process each of the four rectangles, to estimate Simpson's diversity index (described in Nature1949), as follows: A 729 sq. km. (27x27 pixels) quadrat was centered on each pixel of the original land cover map. Simpson's index was then calculated as one minus the sum of the squares of the land cover proportions within the quadrat. The index ranges from zero to one, with larger index values representing greater land cover diversity. The calculated values were discretized to the range [1,255] and stored at one-kilometer spatial resolution. Thus, a pixel value in this data represents the land cover diversity of the surrounding 729 sq. km. on the original land cover map. Pixels representing water were included in the diversity calculations if the pixel at the center of the quadrat was not water, but no calculation was made if the quadrat was centered on a water pixel. The transformation used to discretize the index values was: >D = ( C * 254) + 1 >where >D = discretized value in range [1,255] >C = calculated value of Simpson's index in range [0,1] If needed, the original calculated values can be approximated by applying the back-transformation: >C = (D - 1) / 254 Note that the back-transformed values will be in steps of approximately 0.00394 as a result of the discretization process (precision has been lost). After spatial filtering, the map of diversity index values was constructed by: reassembling the four rectangles into a single image via an in-house software tool named LUMPER.C, which removed the overlapping parts of the rectangles; converting the format to ASCII using the in-house software tool TVA2ASC.C; and finally, bringing the file back into Arc/INFO using the command ASCIIGRID. The georeferencing did not change as a result of reformatting, exporting, and importing, or spatial filtering. The derived map is comparable on a pixel-by-pixel basis to the original land cover map. Source_Used_Citation_Abbreviation: NA_SLCR Source_Used_Citation_Abbreviation: Nature1949 Source_Produced_Citation_Abbreviation: SLDIV27_A Process_Date: 1998 Process_Step: Process_Description: The derived diversity map (SLDIV27_A) was 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. The only difference between the original diversity map projection and the National Atlas projection is the latitude of the projection center, which is 50 degrees 0' 0" in the original map, compared to 45 degrees 0' 0" in the National Atlas. The new projection resulted in a slightly larger cell size (1001.042 meters square) in comparison to the original land cover and diversity maps (1000 meters square). The image was clipped to the study area using the shoreline file, and the land areas without data were added. This was accomplished by defining a grid mask using Arc/INFO's command POLYGRID and specifying a cell size of 1000.984 meters. The clip was done in Arc/INFO GRID by setting the mask and analysis window (SETMASK and SETWINDOW) to the gridded version of STATP075, and overlaying. The resulting map was visually inspected, then exported using the Arc/INFO command EXPORT with the options set to 'grid, no compression'. The standard UNIX compress utility was applied to the exported file. Source_Used_Citation_Abbreviation: STATP075 Source_Used_Citation_Abbreviation: SLDIV27_A Source_Produced_Citation_Abbreviation: LCD729K.E00 Process_Date: 1998 Process_Step: Process_Description: The grid was converted to a TIFF image using the command GRIDIMAGE. Two files were created during the conversion, the TIFF image and a world file (.tfw extension) containing real-world coordinate transformation information. Source_Used_Citation_Abbreviation: LCD729K.E00 Process_Date: 1999 Source_Produced_Citation_Abbreviation: LANDDIV_IMAGE99 Process_Step: Process_Description: A GeoTIFF Revision 1.0 header was added and PackBits compression was applied to the image. Source_Used_Citation_Abbreviation: LANDDIV_IMAGE99 Process_Date: 200205 Source_Produced_Citation_Abbreviation: LANDDIV_IMAGE200205 Process_Step: Process_Description: Image data for Greenland were adjusted and remasked to correct for geometric distortion in the northwest part of the island between the Robeson Channel and Cape Morris Jesup, and to improve registration with a new, corrected coastline derived from World Vector Shoreline (WVS). A link coverage was created in ArcEdit containing links between the original Greenland data and the new coastline. The link coverage was used in the Arc Adjust command to perform a linear transformation with nearest neighbor resampling on the original image, stored as an Arc/INFO grid dataset. The resulting image is geometrically correct and fits the WVS coastline. This correction was applied to data for Greenland only; the rest of the image was left unchanged. Source_Used_Citation_Abbreviation: LANDDIV_IMAGE_200205 Source_Used_Citation_Abbreviation: WVS Process_Date: 200212 Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Raster Raster_Object_Information: Raster_Object_Type: Grid Cell Row_Count: 7265 Column_Count: 10030 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: 1001.042 Ordinate_Resolution: 1001.042 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: Land cover diversity grid cell Entity_Type_Definition: Any of the data elements in the land cover diversity file. Entity_Type_Definition_Source: U.S. Geological Survey Attribute: Attribute_Label: Land cover diversity grid cell value Attribute_Definition: The value is a measure of the variety (diversity) of land cover classes in the area surrounding the grid cell. Diversity is described by a range of values, where smaller values represent less diversity, and larger values represent more diversity. Attribute_Definition_Source: U.S. Geological Survey Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 1 Range_Domain_Maximum: 245 Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: 0 Enumerated_Domain_Value_Definition: Water Enumerated_Domain_Value_Definition_Source: U.S. Geological Survey Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: 255 Enumerated_Domain_Value_Definition: Unlabeled land area Enumerated_Domain_Value_Definition_Source: U.S. Geological Survey 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. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: TIFF Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: Digital_Transfer_Option: Offline_Option: Offline_Media: CD-ROM Recording_Format: tar Fees: There is no charge for the online option. For National Atlas files ordered on CD-ROM there is a base price of $45 per disc, a handling fee of $5, and a per-file charge based on file size. The charge for files less than 10 megabytes in size is $1. The charge for files that range in size from 10 to 150 megabytes is $7.50. The charge for files of 150 megabytes or larger is $15. The charge is $7.50 for the Land Cover Diversity data set. Ordering_Instructions: To order files on CD-ROM, please see . Metadata_Reference_Information: Metadata_Date: 20021220 Metadata_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Peg Rawson Contact_Organization: U.S. Geological Survey Contact_Address: Address_Type: Mailing address Address: 561 National Center 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