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:
Drainage Basin Boundaries, Potomac River Basin, NAWQA, Boundaries,
Water, Hydrography, Fixed Sites
Purpose
The purpose of this data set is to give the Potomac NAWQA study unit
the information needed to do basic spatial analysis for a given watershed
within the Potomac River Basin. One hundred and twenty-seven basin boundaries
were digitized into a Geographic Information System (GIS) and 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
(Gerhart and Brakebill, 1996) were selected out of the original data set.
Supplemental_Information
Procedures_Used
Drainage basin boundaries for U.S. Geological Survey surface-water stations
within the Potomac River Basin (127) were delineated on mylar overlayed on scale
stable USGS 1:100,000 topographic maps. Each quadrangle was digitized using
ARC/INFO software on an Altek 9000 digitizer. Weed tolerances were set
at .001 and snapping tolerances were set at .005. During registration, RMS
errors > .005 were not accepted.
Once digitized in inches, vectors (arcs) were projected into Albers Equal Area
with the following parameters:
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
Arcs were then appended and overshoots & undershoots were corrected.
Polygon topology was then created and labels added. Label points
were attributed with USGS Station Identification numbers (STAID) which
were associated with the proper drainage area for that USGS station
upstream to the next USGS station or the end of the watershed boundary.
In order to address nested watersheds, The INFO item STATION_ID was defined
as an integer (STAID without leading 0) and STAT_MIN was attributed with
the most upstream STATION_ID digitized within a particular watershed. The
ARC RESELECT command was then used on STATION_ID and STAT_MIN to select
out the necessary drainage outlines of fixed site basin boundaries into a
simplified layer once sufficient sampling sites were selected for the
project. ARC: RESELECT STATION_ID <= the STAID requested and >= the STAT_MIN
yielded the entire watershed needed.
For analysis, the STAID & STAT_MIN attributes remain in the
data set and can be used in ARCEDIT in the same fashion they were used
in ARC.
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_SIT - Point coverage of locations of 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, 31 pp.
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
N/A
Status
Progress: Provisional
Maintenance_and_Update_Frequency
None planned.
Spatial_Domain
Bounding_Coordinates
West_Bounding_Coordinate: -79.74150601
East_Bounding_Coordinate: -76.17953713
North_Bounding_Coordinate: 40.22694018
South_Bounding_Coordinate: 37.85990675
Keywords
Theme
Theme_Keyword_Thesaurus: None
Theme_Keyword: Basin Boundaries, NAWQA, Fixed Sites, Potomac
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: Polygon and chain-node topology present.
Completeness_Report
Positional_Accuracy
Horizontal_Positional_Accuracy
Digitized from mylar 1:100,000 USGS topographic map sheets.
Vertical_Positional_Accuracy
Vertical_Positional_Accuracy_Report:
N/A
Lineage: See Supplemental_Information for overview.
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: 12
SDTS_Point_and_Vector_Object_Type: String
Point_and_Vector_Object_Count: 152
SDTS_Point_and_Vector_Object_Type: GT-polygon composed of chains'
Point_and_Vector_Object_Count: 13
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_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: FIXED_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: FIXED_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 Number
Attribute_Definition_Source: USGS
Attribute_Domain_Values
Enumerated_Domain
Enumerated_Domain_Value: Numeric
Enumerated_Domain_Value_Definition
Enumerated_Domain_Value_Definition_Source:
Attribute:
Attribute_Label: STAT_MIN
Attribute_Definition: Most Upstream Station Identification Number
Attribute_Definition_Source: User Defined
Attribute_Domain_Values
Enumerated_Domain
Enumerated_Domain_Value: Numeric
Enumerated_Domain_Value_Definition
Enumerated_Domain_Value_Definition_Source:
Attribute:
Attribute_Label: MI2
Attribute_Definition: Drainage Area in Square Miles
Attribute_Definition_Source: Calculated
Attribute_Domain_Values
Enumerated_Domain
Enumerated_Domain_Value: Alpha
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: User Defined
Attribute_Domain_Values
Enumerated_Domain
Enumerated_Domain_Value: Numeric
Enumerated_Domain_Value_Definition
Enumerated_Domain_Value_Definition_Source:
Entity_Type
Entity_Type_Label: FIXED_BND.AAT
Entity_Type_Definition: Arc Attribute Table
Entity_Type_Definition_Source: ARC/INFO
Attribute:
Attribute_Label: -
Attribute_Definition: Arc Attribute Table
Attribute_Definition_Source: ARC/INFO
Attribute_Domain_Values
Enumerated_Domain
Enumerated_Domain_Value: -
Enumerated_Domain_Value_Definition
Enumerated_Domain_Value_Definition_Source:
Attribute:
Attribute_Label: FNODE#
Attribute_Definition: Internal number of from-node
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: TNODE#
Attribute_Definition: Internal number of to-node
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: LPOLY#
Attribute_Definition: Internal number of poly to left of arc
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: RPOLY#
Attribute_Definition: Internal number of poly to right of arc
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: LENGTH
Attribute_Definition: Length of arc 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: FIXED_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: FIXED_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: LIN
Attribute_Definition: Plotting SYMBOL
Attribute_Definition_Source: USER DEFINED
Attribute_Domain_Values
Enumerated_Domain
Enumerated_Domain_Value: NUMERIC
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 site basin boundaries.e00
Gunzipped SDTS Topological Vector Profile (TVP) format:
Use Load to local disc:
Fixed site basin boundaries.tgz
PC Zipped SDTS Topological Vector Profile (TVP) format:
Fixed 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.
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: 98-02-04.13:29:22.Wed