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, 1992-96
Geospatial_Data_Presentation_Format: map
Scale_Denominator: 24,000
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.
From 1993 - 1995, 89 selected small streams were sampled within 4
different subunits of the Potomac River Basin. This coverage represents the
drainage basin boundaries for these surface-water synoptic sites.
Keywords:
Potomac River Basin, Basin Boundaries, Drainage Boundaries, Synoptic Survey,
Digital, NAWQA, Subunit
Purpose
The purpose of this data is to provide the Potomac NAWQA study unit
with basin boundary information, such as location and area. This coverage
was combined with other spatial data to perform statistical analysis within
the drainage areas in an attempt to relate water quality with natural and
human factors that may affect water quality.
Supplemental_Information
Procedures_Used
Sampling sites were located on U.S. Geological Survey (USGS) 1:24,000 paper
topographic maps. Drainage basin boundaries were delineated on these maps.
Each boundary was digitized into a Geographic Information System using ARC/INFO
Software, a quad sheet at a time. Once the digitizing was complete, each sheet
was projected into ALBERS EQUAL AREA -78 00 00 central meridian. The nodes of
the vector endpoints were adjusted withn a twenty meter radius to match the
nodes from adjacent quad sheets. The vector data (arcs) was then appended
with the data from adjacent quad sheets. Root Mean Square (RMS) errors were
< .005.
Once appended, polygon topology was created and USGS Station Identification
numbers were added to the polygon attribute table (.pat). Boundaries for each
Subunit were compiled separately (Gerhart and Brakebill, 1996). Once all
boundaries for sample sites in all subunits were completed, the basin
boundaries were joined into one coverage (SYN_BND).
Revisions
As needed
Reviews_Applied
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
SYN_SIT - Point coverage of Synoptic 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
ARC/INFO rev. 6.0 was used to begin digitizing. When the final sites of the
last subunit (Valley & Ridge) were completed, ARC/INFO rev 7.0.3 was being used.
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:
Maintenance_and_Update_Frequency
Irregular updates were made only on a case by case basis where errors were
noted. No further updates are planned.
Spatial_Domain
Bounding_Coordinates
West_Bounding_Coordinate: -79.64029495
East_Bounding_Coordinate: -76.88080319
North_Bounding_Coordinate: 39.93998068
South_Bounding_Coordinate: 38.04288582
Keywords
Theme
Theme_Keyword_Thesaurus: None
Theme_Keyword: Potomac NAWQA Synoptic Basin Boundaries
Place
Place_Keyword_Thesaurus: None
Place_Keyword:
Stratum
Stratum_Keyword_Thesaurus: None
Stratum_Keyword:
Temporal
Temporal_Keyword_Thesaurus: None
Temporal_Keyword:
Access_Constraints
NONE
Use_Constraints
This data was digitized from paper 1:24,000 USGS topographic maps. Drainage
basin boundaries were drawn on these quads prior to digitizing.
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: Polygon topology present.
Completeness_Report
Positional_Accuracy
Horizontal_Positional_Accuracy
Horizontal_Positional_Accuracy_Report:
This data was digitized from paper 1:24,000 USGS topographic maps.
Vertical_Positional_Accuracy
Vertical_Positional_Accuracy_Report:
N/A
Lineage: See Supplemental_Information for overview.
Process_Steps
Process_Step
Available in download Arc/Info export file.
Cloud_Cover
N/A
Spatial_Data_Organization_Information
Direct_Spatial_Reference_Method: Vector
Point_and_Vector_Object_Information
SDTS_Terms_Description
SDTS_Point_and_Vector_Object_Type: Point
Point_and_Vector_Object_Count: 89
SDTS_Point_and_Vector_Object_Type: String
Point_and_Vector_Object_Count: 228
SDTS_Point_and_Vector_Object_Type: GT-polygon composed of chains'
Point_and_Vector_Object_Count: 90
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: SYN_BND.PAT
Entity_Type_Definition: Polygon Attribute Table
Entity_Type_Definition_Source: User defined
Attribute:
Attribute_Label: -
Attribute_Definition: Polygon Attribute Table
Attribute_Definition_Source: User defined
Attribute_Domain_Values
Enumerated_Domain
Enumerated_Domain_Value: -
Enumerated_Domain_Value_Definition
Enumerated_Domain_Value_Definition_Source:
Attribute:
Attribute_Label: AREA
Attribute_Definition: Area of poly/region in square coverage units
Attribute_Definition_Source: Computed
Attribute_Domain_Values
Enumerated_Domain
Enumerated_Domain_Value: Positive real numbers
Enumerated_Domain_Value_Definition
Enumerated_Domain_Value_Definition_Source:
Attribute:
Attribute_Label: PERIMETER
Attribute_Definition: Perimeter of poly/region in coverage units
Attribute_Definition_Source: Computed
Attribute_Domain_Values
Enumerated_Domain
Enumerated_Domain_Value: Positive real numbers
Enumerated_Domain_Value_Definition
Enumerated_Domain_Value_Definition_Source:
Attribute:
Attribute_Label: SYN_BND#
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: SYN_BND-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
Attribute_Definition_Source: User defined
Attribute_Domain_Values
Enumerated_Domain
Enumerated_Domain_Value: > 0
Enumerated_Domain_Value_Definition
Enumerated_Domain_Value_Definition_Source:
Attribute:
Attribute_Label: STATION_ID
Attribute_Definition: Station Identification Number
Attribute_Definition_Source: User defined
Attribute_Domain_Values
Enumerated_Domain
Enumerated_Domain_Value: Integer > 0
Enumerated_Domain_Value_Definition
Enumerated_Domain_Value_Definition_Source:
Overview_Description
Entity_and_Attribute_Overview
STAID - Station Identification, 15, 15, Character, used to identify site.
This item is also used in relating other data to the coverage.
NETCODE - Sampling network identification code 12, 12, character
used to identify sampling network
STATION_ID - Redefined item, Station Identification, 7, 7, Integer,
used to identify site as numeric number.
Entity_and_Attribute_Detail_Citation: Not Available
Distribution_Information
Arc/Info Export format:
Use Load to local disc:
Synoptic site basin boundaries.e00
Gunzipped SDTS Topological Vector Profile (TVP) format:
Use Load to local disc:
Synoptic site basin boundaries.tgz
PC Zipped SDTS Topological Vector Profile (TVP) format:
Synoptic site basin boundaries.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.
Cntact
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: 98-02-04.14:31:00.Wed