Metadata: Identification_Information: Citation: Citation_Information: Originator: Roger Tankersley, Jr. Publication_Date: 1998 Title: pop_1970 Edition: 1 Geospatial_Data_Presentation_Form: Map Publication_Information: Publication_Place: Norris TN Publisher: Tennessee Valley Authority Description: Abstract: This map is an ARC/INFO Grid showing population in 1970 on a per-cell basis for the mid-Atlantic region. This Grid was used to determine population per watershed, and was developed using a complex areal interpolation process detailed below. Purpose: These data were created as part of a regional assessment of landscape conditions in the mid-Atlantic region (SFR 3) (Jones et al., 1997). Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: Ending_Date: Currentness_Reference: 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 Keywords: Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: roads Theme_Keyword: population Theme_Keyword: road length ratio Theme_Keyword: Theme_Keyword: Theme_Keyword: 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: USGS 100K DLGs, US Census Historical Population Data. Native_Data_Set_Environment: These data are presently stored in ARC/INFO format. Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: none Logical_Consistency_Report: none Completeness_Report: Complete Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: None Source_Information: Source_Citation: USGS 100K DLGs, US census historical population data.. Citation_Information: Other_Citation_Details: Jones, K.B., Riitters, K.H., Wickham, J.D., Tankersley, R.D., O'Neill, R.V., Chaloud, D.J., Smith, E.R., and Neale, A.C. 1997. An Ecological Assessment of the United States Mid-Atlantic Region: A Landscape Atlas. EPA/600/R97/130, U.S. Environmental Protection Agency, Office of Research and Development, Washington, DC. Source_Information: Source_Citation: Citation_Information: Other_Citation_Details: Process_Step: Process_Description: This Grid is the results of a complex analysis methodology designed to re-apportion population within a county based on road density, so that population can then be determined for each watershed. Our goal was to create a population grid -- where every cell has a determined population -- that could then be used as a data source for summarizing population by watershed. This ratio grid was the crucial starting point. First, we created a 'fishnet', using the ARC/INFO GENERATE command, that covered the entire region with 1 sq. Km. squares. These were to be the sampling units. Then, the CLIP command was used to select out those squares that fall within a particular county; each county was done separately. Once the county fishnet was re-selected, it was intersected with the roads (USGS DLG, class 1-4 roads), so that a value for length of road per sampling block could be computed. This value was then divided by the total road length for the entire county, effectively creating a ratio of total road length for every cell. When totalled, these ratios equal one, representing all roads in the county. Next, the polygon coverage of fishnet ratio values was rasterized for each county, and then all counties were merged into one Grid. At this stage, we have a Grid containing a ratio number for every location in the mid-Atlantic. Population grids were created, where each cell represented the total population for the county that contained it, by using the command POLYGRID with the item cens_1970 in the cnty_pop county coverage. That Grid was then multiplied by the ratio grid. The result is a Grid where population is apportioned using a ratio representing where the roads are, effectively tying roads and population together. This yields a surface map of population per each square kilometer pixel. This Grid was then joined with a Grid representing watershed boundaries, so that population density and percent change could be determined. Source_Used_Citation_Abbreviation: Source_Produced_Citation_Abbreviation: Process_Date: Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: raster Raster_Object_Information: Raster_Object_Type: 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: Entity_Type_Definition: Entity_Type_Definition_Source: ARC/INFO Attribute: Attribute_Label: VALUE Attribute_Definition: Population in 1970. Attribute_Definition_Source: ARC/INFO Attribute_Domain_Values: Range_Domain: Range_Domain_Maximum: Range_Domain_Minimum: Attribute_Measurement_Frequency: None planned Attribute: Attribute_Label:COUNT Attribute_Definition: Number of cells in each population class. Attribute_Definition_Source: ARC/INFO Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: Range_Domain_Maximum: Attribute_Measurement_Frequency: None planned Overview_Description: Entity_and_Attribute_Overview: 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: 19980901 Metadata_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Roger Tankersley, Jr. Contact_Organization: University of Tennessee, Department of Geography Contact_Address: Address_Type: Address: 428 G&G Building Address: City: Knoxville State_or_Province: TN Postal_Code: 37996 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