Water-Quality Assessment of the Potomac River Basin:
Water-Quality and Selected Spatial Data, 1992-96

Selected spatial data --


Identification_Information
     Abstract 
     Purpose 
     Supplemental Information 
Data_Quality_Information
Spatial_Data_Organization_Information
Entity_and_Attribute_Information
     Detailed Description
     Overview 
Distribution_Information
Metadata_Reference_Section


Identification_Information

Citation_Information Originator: Derosier, Brakebill, Denis, Kelley Publication_Date: Title: Water-quality Assessment of the Potomac River Basin: > Water-Quality and selected spatial data, 1992-1996, Geospatial_Data_Presentation_Format: map Scale_Denominator: 100,000

Description Abstract The National Water-Quality Assessment (NAWQA) Program's Potomac River Basin study unit is an integrated water-quality assessment designed to address a broad array of water-quality properties in several environmental media at various spatial and temporal scales. These properties are then related to natural and human factors that can influence the quality of water. During a 3-year period of intensive data collection and analysis, hundreds of water-quality characteristics were measured in five environmental media within surface-water and ground-water systems. Sampled surface-water media include streamwater, streambed sediment, aquatic biological communities, and aquatic biological tissues. This investigation was conducted as part of a nationwide study to help assess the Nation's water-quality conditions. Keywords: Potomac River Basin, NAWQA, Sampling Sites, Water, Hydrography, Fixed Sites Purpose The purpose of this data set is to give the Potomac NAWQA study unit the information necessary to do basic spatial analysis for a given watershed within the Potomac River Basin. One hundred and twenty-seven basin boundaries were used in overlay operations with other geographic data layers such as land use, geology, and physiography in order to provide the information needed for surface-water sampling site selection that met the sampling strategy goals of the study unit and the NAWQA program. Once a sufficient number of sites were selected for the project (11), these basin boundaries representing Basic Fixed Sites were selected out of the original data set. Point coverages of the selected sampling sites (Fixed) were created. Supplemental_Information Procedures_Used Latitude and Longitude coordinates in degrees, minutes, and seconds were retrieved from the U.S.Geological Survey's National Water Inventory System (NWIS) for selected sites. ARC/INFO's CREATEPOINT was used to generate a point coverage of Fixed Sites. The coverage was then attributed with information relative to the project. The projection parameters are listed below. Projection ALBERS Units METERS Spheroid CLARKE1866 Parameters: 1st standard parallel 29 30 0.000 2nd standard parallel 45 30 0.000 central meridian -78 0 0.000 latitude of projections origin 23 0 0.000 false easting (meters) 0.00000 false northing (meters) 0.00000 Revisions As needed after peer review. Reviews_Applied Plots at 1:1 were overlayed on original mylars for accuracy checks. Colleague, District Chief Approval The data you have secured from the USGS have not received Director's approval and as such are provisional and subject to revision. The data are released on the condition that neither the USGS nor the United States Government may be held liable for any damages resulting from their authorized or unauthorized use. Related_Spatial_and_Tabular_Data_Sets FIXED_bnd - Polygon coverage of basin boundaries for fixed sampling sites. Other_References_Cited Blomquist,J.D., Fisher,G.T., Denis,J.M., Brakebill,J.W., and Werkheiser, W.H., 1996, Water-Quality Assessment of the Potomac River Basin: Basin Description and Analysis of Available Nutrient Data, 1970-90. U.S. Geological Survey Water-Resources Investigations Report 95-4221, 88 pp. Gerhart, J.M., and Brakebill, J.W., 1996, Design and Implementation of a Sampling Strategy for a Water-Quality Assessment of the Potomac River Basin U.S. Geological Survey, Water-Resources Investigations Report 96-4034, 31pp. Notes The use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Time_Period_of_Content Currentness_Reference Status Progress: Provisional Maintenance_and_Update_Frequency None planned. Spatial_Domain Bounding_Coordinates West_Bounding_Coordinate: -78.97772092 East_Bounding_Coordinate: -77.10762497 North_Bounding_Coordinate: 39.71277788 South_Bounding_Coordinate: 38.48633823

Keywords Theme Theme_Keyword_Thesaurus: None Theme_Keyword: Potomac NAWQA Basic Fixed Site Locations Place Place_Keyword_Thesaurus: None Place_Keyword: Potomac River Basin Stratum Stratum_Keyword_Thesaurus: None Stratum_Keyword: Temporal Temporal_Keyword_Thesaurus: None Temporal_Keyword:

Access_Constraints NONE Use_Constraints For use at scales of 1:100,000

Data_Set_Credit Security_Information Security_Classification_System: None Security_Classification: UNCLASSIFIED Security_Handling_Description: None

Native_Data_Set_Environment: dgux UNIX, ARC/INFO version 7.0.4

Cross_Reference Originator: Derosier, Brakebill, Denis, Kelley Publication_Date: Publication_Time: Title: Water-quality and selected spatial data, 1992-1996, Potomac River Basin Edition: Geospatial_Data_Presentation_Form: map Series_Information Series_Name: Issue_Identification: Publication_Information Publication_Place: Publisher: Other_Citation_Details: Online_Linkage: Larger_Work_Citation:


Data_Quality_Information

Attribute_Accuracy Attribute_Accuracy_Report: See Entity_Attribute_Information

Quantitative_Attribute_Accuracy_Assessment Attribute_Accuracy_Value: See Explanation Attribute_Accuracy_Explanation: Attribute accuracy is described, where present, with each attribute defined in the Entity and Attribute Section.

Logical_Consistency_Report: Point features present.

Completeness_Report Positional_Accuracy Horizontal_Positional_Accuracy Coordinates calculated from paper U.S. Geological Survey 1:24,000 topographic maps.

Vertical_Positional_Accuracy Vertical_Positional_Accuracy_Report: N/A Lineage: See Supplemental_Information for overview.

Process_Steps Process_Step Available from download Arc/Info export file

Cloud_Cover N/A


Spatial_Data_Organization_Information

Direct_Spatial_Reference_Method: Point
Point_and_Vector_Object_Information SDTS_Terms_Description SDTS_Point_and_Vector_Object_Type: Point Point_and_Vector_Object_Count: 11 SDTS_Point_and_Vector_Object_Type: String Point_and_Vector_Object_Count: 0 SDTS_Point_and_Vector_Object_Type: GT-polygon composed of chains' Point_and_Vector_Object_Count: 0


Spatial_Reference_Information

Horizontal_Coordinate_System_Definition
    Planar
        Map_Projection:
        Map_Projection_Name:  ALBERS
        Longitude_of_Central_Meridian: -78
        Latitude_of_Projection_Origin: 23
        Latitude_of_First_Standard_Parallel: 29.5
        Latitude_of_Second_Standard_Parallel: 45.5
        False_Easting:  0.00000
        False_Northing:  0.00000
    Geodetic Model
        Horizontal_Datum_Name:
        Ellipsoid_Name:  Clarke 1866
        Semi-major_Axis: 6,378,206.4
        Denominator_of_Flattening: 294.98


Entity_and_Attribute_Information

Detailed_Description Entity_Type Entity_Type_Label: FIXED_SIT.PAT Entity_Type_Definition: Point Attribute Table Entity_Type_Definition_Source: USGS Attribute: Attribute_Label: - Attribute_Definition: Point Attribute Table Attribute_Definition_Source: USGS Attribute_Domain_Values Enumerated_Domain Enumerated_Domain_Value: - Enumerated_Domain_Value_Definition Enumerated_Domain_Value_Definition_Source: Attribute: Attribute_Label: AREA Attribute_Definition: Degenerate area of point Attribute_Definition_Source: Assigned Attribute_Domain_Values Enumerated_Domain Enumerated_Domain_Value: 0 Enumerated_Domain_Value_Definition Enumerated_Domain_Value_Definition_Source: Attribute: Attribute_Label: PERIMETER Attribute_Definition: Degenerate perimeter of point Attribute_Definition_Source: Assigned Attribute_Domain_Values Enumerated_Domain Enumerated_Domain_Value: 0 Enumerated_Domain_Value_Definition Enumerated_Domain_Value_Definition_Source: Attribute: Attribute_Label: FIXED_SIT# Attribute_Definition: Internal feature number Attribute_Definition_Source: Computed Attribute_Domain_Values Enumerated_Domain Enumerated_Domain_Value: Sequential unique positive integer Enumerated_Domain_Value_Definition Enumerated_Domain_Value_Definition_Source: Attribute: Attribute_Label: FIXED_SIT-ID Attribute_Definition: User-assigned feature number Attribute_Definition_Source: User-defined Attribute_Domain_Values Enumerated_Domain Enumerated_Domain_Value: Integer Enumerated_Domain_Value_Definition Enumerated_Domain_Value_Definition_Source: Attribute: Attribute_Label: STAID Attribute_Definition: Station Identification Number Attribute_Definition_Source: USGS Attribute_Domain_Values Enumerated_Domain Enumerated_Domain_Value: Character Numeric Enumerated_Domain_Value_Definition Enumerated_Domain_Value_Definition_Source: Attribute: Attribute_Label: SITETYPE Attribute_Definition: Type of Sampling Site Attribute_Definition_Source: USGS NAWQA Attribute_Domain_Values Enumerated_Domain Enumerated_Domain_Value: Character LUIND, PSIND, RFIND, INTGRD Enumerated_Domain_Value_Definition Enumerated_Domain_Value_Definition_Source: Attribute: Attribute_Label: SAMPTYPE Attribute_Definition: Sample Type Collected Attribute_Definition_Source: USGS NAWQA Attribute_Domain_Values Enumerated_Domain Enumerated_Domain_Value: Character INTSV, BASIC, OTHER Enumerated_Domain_Value_Definition Enumerated_Domain_Value_Definition_Source: Attribute: Attribute_Label: STAT_MIN Attribute_Definition: Minimum Station Identification Number up-stream of Site Attribute_Definition_Source: USGS Attribute_Domain_Values Enumerated_Domain Enumerated_Domain_Value: Integer Enumerated_Domain_Value_Definition Enumerated_Domain_Value_Definition_Source: Attribute: Attribute_Label: SYMBOL Attribute_Definition: Cartographic symbol Attribute_Definition_Source: USGS Attribute_Domain_Values Enumerated_Domain Enumerated_Domain_Value: Integer Enumerated_Domain_Value_Definition Enumerated_Domain_Value_Definition_Source: Attribute: Attribute_Label: SITE Attribute_Definition: Internal Site Number Attribute_Definition_Source: USGS NAWQA Attribute_Domain_Values Enumerated_Domain Enumerated_Domain_Value: Character Enumerated_Domain_Value_Definition Enumerated_Domain_Value_Definition_Source: Attribute: Attribute_Label: STRAHLER Attribute_Definition: Strahler Stream Order at Site Based On 1:500,000 data Attribute_Definition_Source: USGS/EPA Attribute_Domain_Values Enumerated_Domain Enumerated_Domain_Value: Integer Enumerated_Domain_Value_Definition Enumerated_Domain_Value_Definition_Source: Attribute: Attribute_Label: STATION_ID Attribute_Definition: Station Identification Number without leading Zero Attribute_Definition_Source: USGS Attribute_Domain_Values Enumerated_Domain Enumerated_Domain_Value: Integer Enumerated_Domain_Value_Definition Enumerated_Domain_Value_Definition_Source:

Overview_Description Entity_and_Attribute_Overview STAID - Station Identification Number (character) STATION_ID - Station Identification Number (Integer) STAT_MIN - Minimum Station Identification Number upstream of site Entity_and_Attribute_Detail_Citation: Not Available


Distribution_Information

Arc/Info Export format: Use Load to local disc:
Fixed sites.e00 Gunzipped SDTS Topological Vector Profile (TVP) format: Use Load to local disc:
Fixed sites.tgz PC Zipped SDTS Topological Vector Profile (TVP) format:
Fixed sites.zip STDS files were created from ARC/INFO ARCSDTS If the end user of an ARCSDTS file does not have access to the SDTSARC command, the file can be converted into an Arc coverage by first uncompressing it with the UNIX gzip command, which will create a UNIX tar file. If the compressed ARCSDTS file does not have a .tgz or .gz suffix, it must be renamed (UNIX mv command) to have one. Second, the user must perform a UNIX tar xvof command on the tar file and all SDTSEXPORT .DDF files will be loaded into the workspace the "tar xvof" command is issued. Last, the user must issue the Arc SDTSIMPORT command with the < in_transfer_prefix > being the first four characters of the prefix to the .DDF files and the < out_cover > being the prefix to the tar file. PC users can use unzip to create STDS .DDF files from downloaded .zip files. Contact John W Brakebill Geographer U.S. Geological Survey 8987 Yellow Brick Road Baltimore, Maryland 21237 Phone: 410-238-4200 Fax: 410-238-4210 email: jwbrakeb@usgs.gov

Metadata_Reference_Section

Metadata_Date: 19980203 Metadata_Contact: jwbrakeb Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata Metadata_Standard_Version: 19940608 Metadata_Time_Convention: Local Time Metadata_Security_Information: Metadata_Security_Classification_System: None Metadata_Security_Classification: UNCLASSIFIED Metadata_Security_Handling_Description: None

Last modified: 98-02-04.13:56:13.Wed