Metadata: Identification_Information: Citation: Citation_Information: Originator: Kurt Riitters, Southern Appalachian Field Laboratory, Biological Resources Division, U.S. Geological Survey Publication_Date: 1998 Title: UINDEX27-9 Edition: 1 Geospatial_Data_Presentation_Form: Map Publication_Information: Publication_Place: Norris, TN Publisher: Tennessee Valley Authority Description: Abstract: This dataset is a grid map that portrays an index of human use, defined as the proportion (area percent) of a defined landscape which has agriculture or urban land cover types (U-Index, O'Neill et al. 1988). The U-Index was calculated at 65.61 ha scale (that is, within 65.61 hectare analysis windows) for the United States Standard Federal Region III (SFR 3) at 30 meter resolution, and stored at 7.29 hectare resolution following median-filtering in 7.29 ha analysis windows. The dataset was created by applying spatial filters to a published map of land cover known as " U.S. Federal Region III Land Cover Data Set", which was obtained from the Multi- Resolution Land Characteristics (MRLC) Consortium. The spatial filter computed the U-Index within 65.61 ha (27x27 pixel) windows from the proportions of land cover types within a window. The [0,1] continuous index was discretized, and a byte representation [1,255] of the index value was stored at the center location in each window. The resulting surface map was then median-filtered by a spatial filter in 7.29 ha (9 x 9 pixel) analysis windows. Purpose: These data were originally created as part of a regional assessment of landscape conditions in the mid-Atlantic region (SFR 3), based on digital land cover maps derived from remote sensing (TM) and produced by the Multi-Resolution Land Characteristics Consortium. The U-Index map portrays relative degrees of human use, considering only the relative area of agriculture plus developed land cover types, and for a single spatial scale. This map was prepared for contextual information and to portray regional conditions, other approaches were used to calculate the Uindex separately for watersheds in SFR 3 for assessment purposes. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 1991 Ending_Date: 1993 Currentness_Reference: Dates of satellite imagery. Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -84 degrees West East_Bounding_Coordinate: -74 degrees West North_Bounding_Coordinate: 43 degrees North South_Bounding_Coordinate: 36 degrees North Keywords: Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: pattern Theme_Keyword: landcover Theme_Keyword: United States Theme_Keyword: agriculture Theme_Keyword: urban Place: Place_Keyword_Thesaurus: None Place_Keyword: United States Place_Keyword: Standard Federal Region III Access_Constraints: None Use_Constraints: None Point_of_Contact: Contact_Information: Contact_Person_Primary: Bruce Jones Contact_Person: Contact_Organization: EPA Landscape Ecology Division Contact_Address: Address_Type: mailing and physical address Address: U.S. Environmental Protection Agency, Box 93478 City: Las Vegas State_or_Province: Nevada Postal_Code: 89193-3478 Contact_Electronic_Mail_Address: jones.bruce@epamail.epa.gov Data_Set_Credit: The basic data from which this map was derived were provided by the Multi-Resolution Land Characteristics Consortium Native_Data_Set_Environment: These data are presently stored in ARC/INFO GRID format. Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: The U-Index is an area density index; the measured variable is the proportion of pixels in an analysis window which have a given land cover type(s) (see Process_Step sections; Riitters et al. 1996). A statistical rule of thumb is that 50 observations are needed in order to accurately estimate a proportion. The analysis window was 27x27 pixels in size, which corresponds to a potential maximum of 729 pixels (less missing values, if any). This index is one of several which could have been used to quantify 'area density', for a discussion of relative strengths and weaknesses please consult a standard textbook on landscape ecology or image processing. 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 [1,255]. Missing values were assigned to cells which were labeled as water on the MRLC land cover map, or which occur outside the boundary of the assessment region. Completeness_Report: Every cell in the original land cover map has a non-zero byte value representing the U-Index, unless the cell was labeled as water in the land cover map. In the latter instance, the cell was assigned a 'missing' data value. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: The positional accuracy of the U-Index map is the same as the positional accuracy of the land cover map from which the U-Index map was derived. Lineage: Source_Information: Source_Citation: Citation_Information: Originator: Publication_Date: 1996 Title: U.S. Federal Region III Land Cover Data Set Edition: Geospatial_Data_Presentation_Form: remote-sensing image Series_Information: Series_Name: U.S. Federal Region III Publication_Information: Publication_Place: Sioux Falls, SD, USA Publisher: Type_of_Source_Media: online Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 1991 Ending_Date: 1993 Source_Currentness_Reference: Dates of satellite imagery. Source_Citation_Abbreviation: MRLC-R3V1 Source_Contribution: Land cover map Source_Information: Source_Citation: Citation_Information: Other_Citation_Details: Riitters, K.H., O'Neill, R.V., and Jones, K. B. 1997. Assessing habitat suitability at multiple scales: a landscape-level approach. Biological Conservation 81:191-202. Source_Information: Source_Citation: Citation_Information: Other_Citation_Details: O'Neill, R.V., with 11 others. 1988. Indices of landscape pattern. Landscape Ecology 1:153-162. Process_Step: Process_Description: Derivation of U-Index from land cover. Land cover data (MRLC-R3V1) obtained from EROS Data Center in Arc Grid format. Individual pixels were re-classified into "U" and "Not U" classes by using the following scheme: Original MRLC class U-class ---------------------------- ------------------------------- 1 - water Missing 2 - low intensity developed U 3 - high intensity developed U 4 - hay/pasture/grass U 5 - row crops U 6 - probable row crops U 7 - conifer forest Not U 8 - mixed forest Not U 9 - deciduous forest Not U 10 - woody wetland Not U 11 - emergent wetland Not U 12 - bare; quarries U 13 - bare; coal mines U 14 - bare; beach Not U 15 - bare; transitional U Land cover data exported to ascii format using the ARC/INFO command GRIDASCII, and format converted to an in-house format using an in-house software tool named ASC2TVA.C. The map was then subdivided into sixteen (16) overlapping rectangles for further processing using an in-house software tool named SPLITTER.C. The rectangles overlapped in order to avoid artifacts near image boundaries during the spatial filtering operations. Each of the 16 sub-rectangles were then processed via spatial filtering to estimate the U-Index as described below. The spatial filtering program is an in-house software tool named SPATCONV.C. Each of the 16 sub-rectangles were then processed via spatial filtering to find the median U-Index in 9x9 pixel windows. The spatial filtering program is an in-house software tool named SPATCONV.C. Results of this step were stored at 270-meter (7.29 ha) resolution. After spatial filtering, the map of area density index values was reconstructed by reversing the steps, including reassembling the 16 sub-rectangles into a single image (via an in-house software tool named LUMPER.C, which removed the overlapping parts of rectangles), converting the format to ascii (using the in-house software tool named TVA2ASC.C), and finally bringing it back into ARC/INFO using their command ASCIIGRID. Note: The georeferencing did not change as a result of reformatting, exporting/importing, or the first spatial filtering step. The second spatial filter (median-filtering) introduced a probable georeferencing error of not more than 270 meters which was deemed acceptable since the purpose of this map was to portray regional trends in a graphic format; other procedures were used to calculate the U-Index separately for each watershed for assessment purposes. Spatial filtering proceeded as follows. A 65.61 ha (27x27 pixels) quadrat was centered on each pixel of the original land cover map. The numbers of "U" and "not U" pixels were then tabulated for the non-missing pixels in the window. The area density index was then computed as the frequency of "U" pixels, divided by the total frequency of non-missing pixels. Note that this expression yields a value of 0 when no "U" pixels are present, and and a value of 1 when all pixels in a window are "U". 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 U-Index of the surrounding 65.61 ha in the original land cover map. Pixels representing water were not included in the area density calculations, and no calculation was made if the quadrat was centered on a water pixel (and a 'missing' value was assigned to the center pixel). The 30-meter U-Index map was then median-filtered using 9x9 pixel windows and the results of this step were stored at 7.29 ha resolution (270 m). A pixel value in this map, then, represents the median value of the U-Index for the 81 30-m pixels in an analysis window before filtering. 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 area density index in range [0,1] If needed, the original calculated values can be approximated by applying the backtransformation: C = (D - 1) / 254 Note that the backtransformed values will be in steps of size approximately 0.00394 as a result of the discretization process (precision has been lost). Source_Used_Citation_Abbreviation: MRLC-R3V1 Source_Produced_Citation_Abbreviation: Process_Date: 1996 Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Raster Raster_Object_Information: Raster_Object_Type: Grid Cell Row_Count: Column_Count: Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Map_Projection: Map_Projection_Name: Lambert_Azimuthal Lambert_Azimuthal: Radius of Sphere of Reference: 6370997 Longitude_of_Central_Meridian: -100 0 0 Latitude_of_Projection_Origin: 45 0 0 False_Easting: 0.0 False_Northing: 0.0 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: Row and column Coordinate_Representation: Abscissa_Resolution: Ordinate_Resolution: Planar_Distance_Units: meters Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: Uindex27-9.VAT Entity_Type_Definition: Value attribute table of Uindex27-9 grid cells Entity_Type_Definition_Source: ARC/INFO Attribute: Attribute_Label: VALUE Attribute_Definition: Byte value representation of U-Index. Attribute_Definition_Source: software computed Attribute_Domain_Values: Range_Domain: Range_Domain_Maximum: 255 (integer) Range_Domain_Minimum: 0 (integer) Attribute_Measurement_Frequency: None planned Attribute: Attribute_Label: COUNT Attribute_Definition: Number of grid cells with indicated VALUE Attribute_Definition_Source: software computed Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: positive integer Range_Domain_Maximum: positive integer Attribute_Measurement_Frequency: None planned Overview_Description: Entity_and_Attribute_Overview: The value attribute table associated with this raster: DATAFILE NAME: Uindex27-9.VAT 2 ITEMS: STARTING IN POSITION 1 COL ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME INDEXED 01 VALUE 4 10 B - - Indexed 05 COUNT 4 10 B - - - Entity_and_Attribute_Detail_Citation: Not available Distribution_Information: Distributor: Contact_Information: Contact_Person_Primary: Contact_Person: Bruce Jones Contact_Organization: EPA Landscape Ecology Division Contact_Address: Address_Type: Address: U.S. Environmental Protection Agency, Box 93478 City: Las Vegas State_or_Province: Nevada Postal_Code: 89193-3478 Contact_Electronic_Mail_Address: jones.bruce@epamail.epa.gov Metadata_Reference_Information: Metadata_Date: 19980902 Metadata_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Kurt Riitters Contact_Organization: U.S. Geological Survey- Biological Resources Division Contact_Address: Address_Type: mailing and physical address Address: NCSU Forestry Dept. Address: 3024-C Biltmore Hall City: Raleigh State_or_Province: NC Postal_Code: 27695 Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata Metadata_Standard_Version: 19940608 Metadata_Security_Information: Metadata_Security_Classification_System: None Metadata_Security_Classification: Unclassified Metadata_Security_Handling_Description: None