| Major Drainage of Loudoun County, VA (2009) | |
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Data format: SDE Feature Class File or table name: GISDBB.GISBROW.MAJDRAINS_LINE Coordinate system: Lambert Conformal Conic Theme keywords: inlandWaters, drainage, drins |
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Abstract:
Major Drains are drainage features in Loudoun County that drain watersheds greater than 640 acres in size. Drainage was originally derived from USDA soil maps. Drainage was recompiled with the soil survey to the County's 1:2400 scale base map. Data were updated and corrected using the photogrammetrically prepared base map. |
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Metadata elements shown with blue text are defined in the Federal Geographic Data Committee's (FGDC) Content Standard for Digital Geospatial Metadata (CSDGM). Elements shown with green text are defined in the ESRI Profile of the CSDGM. Elements shown with a green asterisk (*) will be automatically updated by ArcCatalog. ArcCatalog adds hints indicating which FGDC elements are mandatory; these are shown with gray text.
Major Drains are drainage features in Loudoun County that drain watersheds greater than 640 acres in size. Drainage was originally derived from USDA soil maps. Drainage was recompiled with the soil survey to the County's 1:2400 scale base map. Data were updated and corrected using the photogrammetrically prepared base map.
Major Drains are used in agricultural and farm plans, stormwater management, comprehensive planning, floodplain management, and facility planning.
Field work for the soil survey was first conducted between 1947 and 1952. Soils were originally shown at the scale of 1:15840 and then redrafted to 1:20000; the data were redrafted a final time to fit Loudoun County's base map standard of 1:2400. Although the current data rely heavily on the original soil survey, there have been extensive alterations. The data are updated as field site inspections or interpretation changes occur. Data are stored in the corporate ArcSDE Geodatabase as a line feature class. The coordinate system is Virginia State Plane (North), Zone 4501, datum NAD83 HARN (vertical datum, if applicable, NAVD88), US Survey foot units.
ground condition
Every reasonable effort has been made to assure the accuracy of these data. Loudoun County, Virginia does not assume any liability arising from the use of these data. These data are provided without warranty of any kind, expressed or implied, including, but not limited to, the implied warranties of merchantability and fitness for a particular service. Reliance on these data is at the risk of the user. These data were generated for use by Loudoun County and are available to the public. These data are intended for use at 1:2400 scale or smaller. Acknowledgement of Loudoun County would be appreciated in products derived from this data.
1 Harrison Street SE, 2nd floor
mail stop 60
Retention of attribute accuracy throughout the coverage to geodatabase feature class coversion process was ensured by a QA/QC programmatic check. To meet satisfactory QA/QC requirements the input coverage and output feature class must have, on a record by record basis, identical attribution when comparing all concatenated fields to all the user-defined attribution.
Topologically clean
Features may have been eliminated or generalized due to scale and intended use. To assist Loudoun County, Virginia in the maintenance of the data, please provide any information concerning discovered errors, omissions, or other discrepancies found in the data.
Retention of coordinate accuracy throughout the coverage to geodatabase feature class conversion process was ensured by a QA/QC programmatic check. To meet satisfactory QA/QC requirements the input coverage and output feature class must have the same record total, and on a record by record basis, area, perimeter, and length differential of less than +/- 0.5%.
Data derived from USDA soil maps
Data derived from USDA soil maps
Drainage was recompiled with the soil survey to the County's 1:2400 scale base map. Data were updated and corrected using the photogrammetrically prepared base map. Major Drains were extracted from data, which drain watersheds greater than 640 acres in size.
This data set was part of a batch process that converted legacy data from ArcInfo coverage in Librarian to a single-tiled ArcInfo coverage in preparation for a final coversion to ArcSDE Geodatabase Feature Classes. Data were extracted from Librarian using the EXTRACT TOPOLOGICAL command. Multi-tiled data sets were extracted into multiple coverages and then combined based on the feature type(s). Layers with both polygon and arc feature classes were processed with the Arc commands, MAPJOIN and DISSOLVE. Arc feature classes alone were processed with the Arc commands, APPEND and DISSOLVE. Layers with both arc and point feature classes and point feature classes alone were processed with the Arc command, APPEND. When used, the Arc command, DISSOLVE, was given with the <#all> option. All coverages were then reprojected to HARN 83 using the following .prj file specifications: INPUT PROJECTION STATEPLANE UNITS FEET ZONE 5551 DATUM NAD27 NADCON PARAMETERS OUTPUT PROJECTION STATEPLANE UNITS FEET FIPSZONE 4501 DATUM HPGN NADCON PARAMETERS END This dataset was then converted to a feature class in a geodatabase in ArcSDE.
Classification of stream
Loudoun County
Stream ID, not maintained
Loudoun County
Internal feature number.
ESRI
Area of drainage by feature
Loudoun County
> 640 acres
Name of drainage feature
Louodun County
Source that created or edited feature class
Loudoun County
Date feature class created or modified
Loudoun County
Feature geometry.
ESRI
Not for public distribution. Internal USER ID of editor creating or modifying feature class
Loudoun County
MA_DRAIN: Classification of stream
Value Classification 0 1 2 3 4
MA_UPD_SOURCE: source by which feature was created or modified
Source Definition 0 Undetermined 1 Legacy 2 County 3 Contract
1 Harrison Street S.E., 2nd floor
MS 65
Every reasonable effort has been made to assure the accuracy of these data. Loudoun County, Virginia does not assume any liability arising from the use of these data. These data are provided without warranty of any kind, either expressed or implied, including, but not limited to, the implied warranties of merchantability and fitness for a particular service. Reliance on these data is at the risk of the user.
ESRI Personal Geodatabase Feature Class
ESRI Shapefile
AutoCad Digital Exchange File
Size limit: 4.5 GB. Visit our website at: http://www.loudoun.gov/omagi, click on "Loudoun County Mapping Documents & Order Forms." The "Forms" directory will lead you to custom & standard (countywide) data order forms. Hardcopy maps may also be available; please contact the Mapping Office Public Information Counter for more information regarding all data requests.
1 Harrison Street SE, 2nd Floor
MS 65