Digital Data Used to Relate Nutrient Inputs to Water Quality in the Chesapeake Bay Watershed, Version 2.0

Appendix: Metadata for Digital Data Sets

• Water-Quality Data, SPARROW version II

  • Online_Linkage:
    • Arc/Info Export format from NT, NT 4.0 at SP6, ARC/INFO version 7.2.1: Use Load to local disc: q2_sit.e00
    • ArcView shapefile, NT 4.0 at SP6, ArcView 3.2 Use Load to local disc: q2_sit_shp.zip

• Network

  • Segmented-Watershed Network (SPARROW, version II)

    • Online_Linkage:
      • Polygon Version
        • Arc/Info Export format from NT, NT 4.0 at SP6, ARC/INFO version 7.2.1: Use Load to local disc:
          Cbws_v2.e00
        • ArcView shapefile, NT 4.0 at SP6, ArcView 3.2 Use Load to local disc:
          cbws_v2_shp.zip
      • Raster Version (GRID)- See instructions at bottom of page
        • ASCII Format Unzipped, this text file exceeds 2 gigabytes. Use Load to Local Disc:
          ASCII GRID cbws_txt.zip
        • Projection File
          cbws_g2.prj

  • Reach Network (SPARROW, version II)

    • Online_Linkage:
      • Arc/Info Export format from NT, NT 4.0 at SP6, ARC/INFO version 7.2.1: Use Load to local disc:
        erf1_2.e00
      • ArcView shapefile, NT 4.0 at SP6, ArcView 3.2 Use Load to local disc: erf1_2_shp.zip

• Nutrient-Input Sources

  • Atmospheric Deposition, 1992

    • Online_Linkage:
      • Raster Version (GRID)- See instructions at bottom of page ASCII format: Use Load to local disc:
        atdep92_g.txt
      • Projection File
        atdep92_g.prj
      • Mean values by SPARROW watershed segment ASCII format: Use Load to local disc:
        atdep92.mean

  • Septic Systems, 1990

    • Online_Linkage:
      • Arc/Info Export format NT 4.0 at SP6, ARC/INFO version 7.2.1: Use Load to local disc:
        septic90.e00
      • ArcView shapefile, NT 4.0 at SP6, ArcView 3.2 Use Load to local disc: septic90_shp.zip

  • Point Sources, 1990-92

    • Online_Linkage:
      • Arc/Info Export format from dgux, NT 4.0 at SP6, ARC/INFO version 7.2.1: Use Load to local disc:
        pntsrc92.e00
      • ArcView shapefile, NT 4.0 at SP6, ArcView 3.2 Use Load to local disc: pntsrc92_shp.zip

  • Loads From Agricultural Sources, 1992

    • Online_Linkage:
      • Arc/Info Export format from NT, NT 4.0 at SP6, ARC/INFO version 7.2.1: Use Load to local disc:
        agld92.e00
      • ArcView shapefile, NT 4.0 at SP6, ArcView 3.2 Use Load to local disc: agld92_shp.zip

• Land-Surface Characteristics

  • Precipitation, 1950-94

    • Online_Linkage:
      • With the exception of PRECIP.MEAN, the following data represents the same information distributed in the report Digital Data Used to Relate Nutrient Inputs to Water Quality in the Chesapeake Bay Watershed, Version 1.0.
      • Arc/Info Export format (GRID) from NT, NT 4.0 at SP6, ARC/INFO version 7.2.1: Use Load to local disc:
        precip.e00
      • ASCII format: (GRID) - see NOTES at bottom of page Use Load to local disc:
        precip.txt
      • ASCII format: Use Load to local disc:
        precip.mean - Mean values by 1992 SPARROW watershed segment

  • Temperature, 1950-94

    • Online_Linkage:
      • With the exception of TEMP.MEAN, the following data represents the same information distributed in the report Digital Data Used to Relate Nutrient Inputs to Water Quality in the Chesapeake Bay Watershed, Version 1.0.
        • Arc/Info Export format (GRID) from NT, NT 4.0 at SP6, ARC/INFO version 7.2.1: Use Load to local disc:
          temp.e00
        • ASCII format:(GRID) - see NOTES at bottom of page Use Load to local disc:
          temp.txt
        • ASCII format: Use Load to local disc:
          temp.mean- Mean values by 1992 SPARROW watershed segment

  • Slope

    • Online_Linkage:
      • With the exception of SLOPE.MEAN, the following data represents the same information distributed in the report Digital Data Used to Relate Nutrient Inputs to Water Quality in the Chesapeake Bay Watershed, Version 1.0.
        • Arc/Info Export format (GRID) from NT, NT 4.0 at SP6, ARC/INFO version 7.2.1: Use Load to local disc:
          slope.e00
        • ASCII format:(GRID) - see NOTES at bottom of page Use Load to local disc:
          slope.txt
        • ASCII format: Use Load to local disc:
          slope.mean- Mean values by 1992 SPARROW watershed segment

  • Soil Permeability

    • Online_Linkage:
      • With the exception of PERM.MEAN, the following data represents the same information distributed in the report Digital Data Used to Relate Nutrient Inputs to Water Quality in the Chesapeake Bay Watershed, Version 1.0.
        • Arc/Info Export format (GRID) from NT, NT 4.0 at SP6, ARC/INFO version 7.2.1: Use Load to local disc:
          perm.e00
        • ASCII format:(GRID) - see NOTES at bottom of page Use Load to local disc:
          perm.txt
        • ASCII format: Use Load to local disc:
          perm.mean-Mean values by 1992 SPARROW watershed segment

  • Nutrient Yield Estimates, SPARROW version II, 1992 land-surface conditions

    • Online_Linkage:
      • ArcView shapefile, NT 4.0 at SP6, ArcView 3.2 Use Load to local disc: Total Nitrogen Yield Estimates tnnye_shp.zip Total Phosphorus Yield Estimates tpnye_shp.zip
      • ASCII format: Use this data in conjunction with the Segmented-Watershed Network to display
      • Use Load to local disc: See Metadata for item descriptions
        ASCII data file for Total Nitrogen and Total Phosphorus Yield Estimates tntp.txt

**NOTES**

Vector data sets for Version II (1992) are distributed in ARC/INFO export (.e00) format. Some raster data sets from Version I (1987) used in Version II are distributed in .e00 format as well. SDTS format are available upon request. Some data sets are ArcView Shapefiles. Raster data used in Version II (1992) are distributed in ASCII (.txt) format.

Average data (*.mean) files are distributed in ASCII comma delimited format. They represent average values by SPARROW watershed segments, Version II. The first column in the unique reach isentification number (E2RF1##). The second column is the average value for that watershed.

All shapefiles and associated data are compressed in .zip files. All shapefiles were generated with the ARCSHAPE command.

Text (.txt) files representing raster data are ASCII files created from ARC/INFO GRIDASCII where xxx is a number, and the keyword nodata_value is optional and defaults to -9999. The end of each row is terminated with a carriage return in the file.

To load .txt Files representing raster data into ArcView,

1. Uncompress the file if it has a .zip extension (<filename>.zip)

2. Start Arcview GIS and be sure the Spatial Analyst extension is turned on. The do this, select File and Extensions... and check the Spatial Analyst.

3. Open existing or start a new project. Open and/or make a View active.

4. Import the gridded ASCII file you by selecting File and then Import Grids.... The Import File Type should be set to ASCII.

5. In the Import ASCII Files dialog box, change the "List Files of Type" to All Files (*.*). Select the unzipped ASCII file.

6. At this point you must provide Arcview GIS with an output file name (the default is imgrd1) for the imported grid. Be sure you are saving in the correct directory and then type in the filename.

7. At the dialog box "Import Grids: ..." Cell values as integers? Select "yes."

8. Now go to a View, and add a theme. In the Add Theme dialog box, change type of theme from Featured Data Source to Gridded Data Source. Then simply select the imported grid that you saved in step 6.

Return to report -- Digital Data Used to Relate Nutrient Inputs to Water Quality in the Chesapeake Bay, Version 2.0

Maintainer: John Brakebill jwbrakeb@usgs.gov Last modified: 10/10/01