Road Casings of Loudoun County, VA (2020)

Metadata:

• Identification_Information
• Data_Quality_Information
• Spatial_Data_Organization_Information
• Spatial_Reference_Information
• Entity_and_Attribute_Information
• Distribution_Information
• Metadata_Reference_Information

Identification_Information:

Citation:

Citation_Information:

Originator:

Loudoun County, Virginia, Office of Mapping and Geographic Information (OMAGI)

Publication_Date: 20210427

Title: Road Casings of Loudoun County, VA (2020)

Geospatial_Data_Presentation_Form: vector digital data

Description:

Abstract:

Road Casings are a base map data layer derived by automated processes and processed for cartographic representation at 1:2400 scale. Captured as polygons, these features represent roads, parking lots, driveways, runways and a unique Bicycle/Equestrian trail, the W Railroad Regional Parka s seen from above and are mapped to National Map Accuracy Standards (NMAS). A separate item or field will capture surface permeability attribution (paved or unpaved) for each feature.

Purpose:

Roads are used as reference in the maintenance of parcel and other data; they also are used in a variety of studies, including the determination of impervious surface. The County has two road coverages: road_casing and road_centerline. Although the casing coverage is the most accurate, as it was updated photo-grammetrically, it is usually not the most current. The road_centerline coverage is the most current, as it is maintained in house from plats submitted by engineering firms. Design changes that can occur between recordation and construction, however, may result in deviation between road_centerline and the real world.

Supplemental_Information:

Data are stored in the corporate ArcSDE Geodatabase as a polygon feature class. The coordinate system is Virginia State Plane (North), Zone 4501, datum NAD83 HARN, Vertical datum, NAVD88, US Survey foot units.
OMAGI updates all base map data via photogrammetric process, using aerial imagery that is flown yearly. A different portion of the county is updated each year with the base map maintenance services contract, depending upon development patterns and update funding. The field “UPD_DATE” indicates the date a feature was last re-mapped. For a map of the most recent reviews and updates within the county, please click on https://arcg.is/0Tm9PW0

Status:

Progress: Complete

Maintenance_and_Update_Frequency: Annually

Spatial_Domain:

Bounding_Coordinates:

West_Bounding_Coordinate: -77.964580

East_Bounding_Coordinate: -77.314024

North_Bounding_Coordinate: 39.326438

South_Bounding_Coordinate: 38.836941

Keywords:

Theme:

Theme_Keyword_Thesaurus: none; Employee generated

Theme_Keyword: lot

Theme_Keyword: transportation

Theme_Keyword: casing

Theme_Keyword: runway

Theme_Keyword: pavement

Theme_Keyword: driveway

Theme_Keyword: highway

Theme_Keyword: W&OD

Theme_Keyword: road

Theme_Keyword: parking

Theme_Keyword: street

Theme_Keyword: shoulder

Theme:

Theme_Keyword_Thesaurus: ISO 19115 Topic Categories

Theme_Keyword: transportation

Place:

Place_Keyword_Thesaurus: none; Employee generated

Place_Keyword: County

Place_Keyword: Loudoun

Place_Keyword: Virginia

Place_Keyword: W&OD trail

Access_Constraints: None

Use_Constraints:

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.

Point_of_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: Loudoun County, VA, OMAGI

Contact_Position: Base Map Coordinator

Contact_Address:

Address_Type: mailing and physical

Address: MS 65

Address: 1 Harrison Street SE, 2nd Floor

City: Leesburg

State_or_Province: VA

Postal_Code: 20175

Country: US

Contact_Voice_Telephone: (703)771-5778

Contact_Facsimile_Telephone: (703)771-5075

Contact_Electronic_Mail_Address: mapping@loudoun.gov

Hours_of_Service: 8:00-4:30 EST, M-F

Native_Data_Set_Environment:

Microsoft Windows Server 2008 Version 6.0 (Build 6002) Service Pack 2; ESRI ArcGIS 10.0.5.4400

Data_Quality_Information:

Attribute_Accuracy:

Attribute_Accuracy_Report:

Transportation has undergone extensive Quality Assurance procedures to ensure feature attribution is consistent with the data dictionary and adheres to a logical relationship with neighboring features and layers.

Quantitative_Attribute_Accuracy_Assessment:

Attribute_Accuracy_Value: >90% attribute accuracy exists

Attribute_Accuracy_Explanation:

27 separate block study areas underwent QA/QC comparison with the source orthophoto and overlaying base map layers. Greater than 90% of all features in each block achieve correct TYPE attribution. OMAGI compiled a separate PGDB for known attribute errors above 90% threshold.

Logical_Consistency_Report: Topologically clean

Completeness_Report:

Base Map features have been updated from different sources and in different years. Although the entire county was originally mapped, users should be cautious and aware that any particular area of interest may not be absolutely current and up to date. A generalized map of update years can be located at the OMAGI's webpage. The next anticipated update shall occur using 2016 imagery.

Positional_Accuracy:

Horizontal_Positional_Accuracy:

Horizontal_Positional_Accuracy_Report:

Accuracy Assessments have been computed according to The National Standard for Spatial Data Accuracy (NSSDA). NSSDA implements a statistical and testing methodology for estimating the positional accuracy of points on maps and in digital geospatial data with respect to georeferenced ground positions of higher accuracy. Accuracy is reported in ground distances at the 95% confidence level. Accuracy reported at the 95% confidence level means that 95% of the positions in the dataset will have an error with respect to true ground position that is equal to or smaller than the reported accuracy value. Data has been tested and meets NSSDA and ASPRS accuracy requirements for 1:2400 scale maps.

Vertical_Positional_Accuracy:

Vertical_Positional_Accuracy_Report: Not Available

Lineage:

Source_Information:

Source_Citation:

Citation_Information:

Publication_Date: 20020304

Title: Base Map Maintenance Services Contract, QQ-00986, Phase I

Geospatial_Data_Presentation_Form: remote-sensing image

Source_Scale_Denominator: 2400

Type_of_Source_Media: None

Source_Citation_Abbreviation: Base Map Maintenance Services Contract, QQ-00986, Phase I

Source_Contribution:

Captured Western 2/3 of County generally located north of Leesburg, west of Rt. 621, Evergreen Mills Rd, and south of Braddock Rd.

Source_Information:

Source_Citation:

Citation_Information:

Originator: Loudoun County, VA, OMAGI

Publication_Date: 20040308

Title: Base Map Maintenance Services Contract, QQ-00986, Phase II

Geospatial_Data_Presentation_Form: Remote sensing image

Source_Scale_Denominator: 2400

Type_of_Source_Media: None

Source_Citation_Abbreviation: Base Map Maintenance Services Contract, QQ-00986, Phase II

Source_Contribution:

Captured Eastern 1/3 of County generally located to include Leesburg, east of Rt. 621, Evergreen Mills Rd, and north of Braddock Rd.

Source_Information:

Source_Citation:

Citation_Information:

Originator: Loudoun County, VA, OMAGI

Publication_Date: 20050307

Title: Base Map Maintenance Services Contract, QQ-00986, Phase III

Geospatial_Data_Presentation_Form: remote-sensing image

Source_Scale_Denominator: 2400

Type_of_Source_Media: None

Source_Citation_Abbreviation: Base Map Maintenance Services Contract, QQ-00986, Phase III

Source_Contribution:

Captured photogrammetric stereo models covering highest development areas in the original Phase I region and including Leesburg.

Source_Information:

Source_Citation:

Citation_Information:

Publication_Date: 20070305

Title: Base Map Maintenance Services Contract, QQ-00986, Phase IV

Source_Scale_Denominator: 2400

Type_of_Source_Media: None

Source_Citation_Abbreviation: Base Map Maintenance Services Contract, QQ-00986, Phase IV

Source_Contribution:

Captured and updated photogrammetric stereo models covering highest development areas in the original Phase II region.

Source_Information:

Source_Citation:

Citation_Information:

Publication_Date: 20080303

Title: Base Map Maintenance Services Contract, QQ-01407, 2008

Source_Scale_Denominator: 2400

Type_of_Source_Media: None

Source_Citation_Abbreviation: Base Map Maintenance Services Contract, QQ-01407, 2008

Source_Contribution:

Captured and updated photogrammetric stereo models covering highest development areas in the north eastern region.

Source_Information:

Source_Citation:

Citation_Information:

Originator: Loudoun County, VA, OMAGI

Publication_Date: 20090302

Title: Base Map Maintenance Services Contract, QQ-01407, 2008

Geospatial_Data_Presentation_Form: remote-sensing image

Source_Scale_Denominator: 2400

Type_of_Source_Media: None

Source_Citation_Abbreviation: Base Map Maintenance Services Contract, QQ-01407, 2008

Source_Contribution:

Captured and updated photogrammetric stereo models covering highest development areas in the western region.

Source_Information:

Source_Citation:

Citation_Information:

Publication_Date: 20130514

Title: Base Map Maintenance Services Contract, QQ-01407, 2012

Source_Scale_Denominator: 2400

Type_of_Source_Media: None

Source_Citation_Abbreviation: Base Map Maintenance Services Contract, QQ-01407, 2012

Source_Contribution:

Captured and updated photogrammetric stereo models covering highest development areas in the western region.

Process_Step:

Process_Description:

Aerial film was acquired and imaged in 2002 (Virginia Base Mapping Program (VBMP) color) and 2004 (Loudoun County annual aerial mission (black & white). The imagery was scanned at 21 microns. Ground control used to support the compilation and was collected by identifying strategic locations on the aerial photography plan and then determining the coordinates by GPS ground survey techniques. The Aerial Triangulation was performed using softcopy workstations. Bundle adjustment was performed and Digital Elevation Models were created using and planimetric data were collected using standard photogrammetric collection techniques for breaklines and masspoints on soft copy workstations. Final deliverables in ESRI Interchange (E00) file format were placed on CD for delivery to OMAGI.

Process_Date: 20040202

Process_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: Loudoun County, VA, OMAGI

Process_Step:

Process_Description:

1. Legacy PGDB converted to DWG file. 2. DWG File imported to Microstation V8, and overlaid with the Update Parcels DGN. Identified Areas to be corrected. 3. Remap area inside parcel change layer a. If no change is detected the entities are not modified b. If new features are found they are collected as per the specifications c. If there is difference in shape or size of the planimetric, environmental or topographic features these are modified and coded as Update_Date = '2005' 4. Review remainder of model area outside the parcel change area a. If new features found they are collected as per the specifications 5. Updated Plan data in the Parcel areas have been checked for Edge matching 6. DTM was modified in the 11 major update areas 7. Contours were generated and edge matched with the legacy contour data 8. Checked contour coding at all the new buildings. 9. Checked the updated data on Ortho for completeness 10. All clean up tools have been run 11. Exported to Coverages and then to GDB. 12. Split the Area wise GDB into manageable pieces 13. Run QA/QC on each part of the Area wise GDB 14. Errors marked in the Log file have been corrected in the merged database 15. Merged the different Areas data into a single GDB i.e., Pilot, Areas 1, 2, & 4 16. Dissolved the polygons with same feature codes 17. Clipped legacy data to Phase 3 delivery boundary 18. Loaded new Phase 3 data and merged with existing Legacy data in east. 19. Loaded complete data sets (11) to enterprise SDE geodatabase

Process_Date: 20050103

Process_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: Loudoun County, VA, OMAGI

Contact_Position: Base Map Cartographer

Process_Step:

Process_Description:

Each of the Base Map Data Layer coverages in the 27 delivery blocks comprising Phases I and II were loaded into a single Geodatabase Feature Class using ArcGIS Simple Data Loader. The entire feature class was then dissolved using ArcToolBox Dissolve, such that any adjacent features with identical values in all attributes consolidated into one feature. Record Counts, Frequencies, Length or Area summaries and final Topology checks were performed throughout the conversion procedure to ensure that multiple coverage data input matched single feature class data output (per TYPE code). 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%

Process_Date: 20050124

Process_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: Loudoun County, VA, OMAGI

Contact_Position: Base Map Cartographer

Process_Step:

Process_Description:

1. Legacy PGDB converted to DWG file. 2. DWG file imported to micro station V8 and overlaid with the area to be remapped. 3. New features were collected as per the data dictionary and the features that do not exist on 2007 imagery were deleted. 4. Modifications were done if there was a change in the shape and size of the features. 5. All the new and updated features were modified and coded as Update_Date= '2007'. 6. Updated data was checked for edge matching. 7. DTM was modified in the update area. 8. Contours were generated, coded and edge matched with the legacy contour data. 9. Spot Elevation Points were placed. 10. All clean up tools were run. 11. Data was exported to PGDB. 12. QA/ QC Program was run and reported errors were corrected. 13. Updated data was checked against Orthos for completeness. 14. All the delivery blocks were merged into a single PGDB. 15. Legacy PGDB was clipped to Phase 4 delivery boundary. 16. Updated Data was merged with the Legacy data. 17. Countywide complete dataset (11 layers) was loaded to enterprise SDE Geodatabase.

Process_Date: 20070611

Process_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: Loudoun County, VA, OMAGI

Process_Step:

Process_Description:

1. Legacy PGDB converted to DWG file. 2. DWG file imported to micro station V8 and overlaid with the area to be updated. 3. New features were collected as per the data dictionary and the features that do not exist on 2008 imagery were deleted. 4. Modifications were done if there was a change in the shape and size of the features. 5. All the new and updated features were modified and coded as Update_Date= '2008'. 6. Updated data was checked for edge matching. 7. DTM was modified in the update area. 8. Contours were generated, coded and edge matched with the legacy contour data. 9. Spot Elevation Points were placed. 10. All clean up tools were run. 11. Data was exported to PGDB. 12. QA/ QC Program was run and reported errors were corrected. 13. Updated data was checked against Orthos for completeness. 14. All the delivery blocks were merged into a single PGDB. 15. Updated Data was merged with the Legacy data. 16. Countywide complete dataset (11 layers) was loaded to enterprise SDE Geodatabase.

Process_Date: 20090907

Process_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: Loudoun County, VA, OMAGI

Contact_Position: Base Map Cartographer

Process_Step:

Process_Description:

1. Legacy PGDB converted to DWG file. 2. DWG file imported to micro station V8 and overlaid with the area to be updated. 3. New features were collected as per the data dictionary and the features that do not exist on 2009 imagery were deleted. 4. Modifications were done if there was a change in the shape and size of the features. 5. All the new and updated features were modified and coded as Update_Date= '2009'. 6. Updated data was checked for edge matching. 7. DTM was modified in the update area. 8. Contours were generated, coded and edge matched with the legacy contour data. 9. Spot Elevation Points were placed. 10. All clean up tools were run. 11. Data was exported to PGDB. 12. QA/ QC Program was run and reported errors were corrected. 13. Updated data was checked against 2009 Orthos for completeness. 14. All the delivery blocks were merged into a single PGDB. 15. Updated Data was merged with the Legacy data. 16. Countywide complete dataset (11 layers) was loaded to enterprise SDE Geodatabase.

Process_Date: 20101011

Process_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: Loudoun County, VA, OMAGI

Process_Step:

Process_Description:

1. Legacy PGDB converted to DWG file. 2. DWG file imported to micro station V8 and overlaid with the area to be updated. 3. New features were collected as per the data dictionary and the features that do not exist on 2012 imagery were deleted. 4. Modifications were done if there was a change in the shape and size of the features. 5. All the new and updated features were modified and coded as Update_Date= '2012'. 6. Updated data was checked for edge matching. 7. DTM was modified in the update area. 8. Contours were generated, coded and edge matched with the legacy contour data. 9. Spot Elevation Points were placed. 10. All clean up tools were run. 11. Data was exported to PGDB. 12. QA/ QC Program was run and reported errors were corrected. 13. Updated data was checked against 2012 Orthos for completeness. 14. All the delivery blocks were merged into a single PGDB. 15. Updated Data was merged with the Legacy data. 16. Countywide complete dataset (11 layers) was loaded to enterprise SDE

Process_Date: 20130514

Process_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: Loudoun County, VA, OMAGI

Source_Information:

Source_Citation:

Citation_Information:

Title: Base Map Maintenance Services Contract, QQ-01407, 2013

Publication_Date: 20140514

Source_Scale_Denominator: 2400

Type_of_Source_Media: None

Source_Citation_Abbreviation: Base Map Maintenance Services Contract, QQ-01407, 2013

Source_Contribution:

Captured and updated photogrammetric stereo models covering selected areas in the central region of Loudoun County.

Process_Step:

Process_Description:

1. Legacy PGDB converted to DWG file. 2. DWG file imported to micro station V8 and overlaid with the area to be updated. 3. New features were collected as per the data dictionary and the features that do not exist on 2013 imagery were deleted. 4. Modifications were done if there was a change in the shape and size of the features. 5. All the new and updated features were modified and coded as Update_Date= '2013'. 6. Updated data was checked for edge matching. 7. DTM was modified in the update area. 8. Contours were generated, coded and edge matched with the legacy contour data. 9. Spot Elevation Points were placed. 10. All clean up tools were run. 11. Data was exported to PGDB. 12. QA/ QC Program was run and reported errors were corrected. 13. Updated data was checked against 2013 Orthos for completeness. 14. All the delivery blocks were merged into a single PGDB. 15. Updated Data was merged with the Legacy data. 16. Countywide complete dataset (11 layers) was loaded to enterprise SDE

Process_Date: 20140514

Process_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: Loudoun County, VA, OMAGI

Source_Information:

Source_Citation:

Citation_Information:

Publication_Date: 20150803

Title: Base Map Maintenance Services Contract, QQ-01857, 2014

Source_Scale_Denominator: 2400

Type_of_Source_Media: None

Source_Citation_Abbreviation: Base Map Maintenance Services Contract, QQ-01857, 2014

Source_Contribution:

Captured and updated photogrammetric stereo models covering selected areas in the central region of Loudoun County.

Process_Step:

Process_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: Loudoun County, VA, OMAGI

Process_Description:

1. Legacy PGDB converted to DWG file. 2. DWG file imported to micro station V8 and overlaid with the area to be updated. 3. New features were collected as per the data dictionary and the features that do not exist on 2014 imagery were deleted. 4. Modifications were done if there was a change in the shape and size of the features. 5. All the new and updated features were modified and coded as Update_Date= '2014'. 6. Updated data was checked for edge matching. 7. DTM was modified in the update area. 8. Contours were generated, coded and edge matched with the legacy contour data. 9. Spot Elevation Points were placed. 10. All clean up tools were run. 11. Data was exported to PGDB. 12. QA/ QC Program was run and reported errors were corrected. 13. Updated data was checked against 2014 Orthos for completeness. 14. All the delivery blocks were merged into a single PGDB. 15. Updated Data was merged with the Legacy data. 16. Countywide complete dataset (11 layers) was loaded to enterprise SDE

Process_Date: 20150803

Process_Step:

Process_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: Loudoun County, VA, OMAGI

Process_Description:

1. Legacy PGDB converted to DWG file. 2. DWG file imported to micro station V8 and overlaid with the area to be updated. 3. New features were collected as per the data dictionary and the features that do not exist on 2015 imagery were deleted. 4. Modifications were done if there was a change in the shape and size of the features. 5. All the new and updated features were modified and coded as Update_Date= '2015'. 6. Updated data was checked for edge matching. 7. DTM was modified in the update area. 8. Contours were generated, coded and edge matched with the legacy contour data. 9. Spot Elevation Points were placed. 10. All clean up tools were run. 11. Data was exported to PGDB. 12. QA/ QC Program was run and reported errors were corrected. 13. Updated data was checked against 2015 Orthos for completeness. 14. All the delivery blocks were merged into a single PGDB. 15. Updated Data was merged with the Legacy data. 16. Countywide complete dataset (11 layers) was loaded to enterprise SDE

Process_Date: 20160825

Source_Information:

Source_Scale_Denominator: 2400

Type_of_Source_Media: None

Source_Citation_Abbreviation: Base Map Maintenance Services Contract, QQ-01857, 2015

Source_Contribution:

Captured and updated photogrammetric stereo models covering selected areas in the central region of Loudoun County.

Process_Step:

Process_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: Loudoun County, VA, OMAGI

Process_Description:

1. Legacy PGDB converted to DWG file. 2. DWG file imported to micro station V8 and overlaid with the area to be updated. 3. New features were collected as per the data dictionary and the features that do not exist on 2016 imagery were deleted. 4. Modifications were done if there was a change in the shape and size of the features. 5. All the new and updated features were modified and coded as Update_Date= '2016. 6. Updated data was checked for edge matching. 7. DTM was modified in the update area. 8. Contours were generated, coded and edge matched with the legacy contour data. 9. Spot Elevation Points were placed. 10. All clean up tools were run. 11. Data was exported to PGDB. 12. QA/ QC Program was run and reported errors were corrected. 13. Updated data was checked against 2016 othos for completeness. 14. All the delivery blocks were merged into a single PGDB. 15. Updated Data was merged with the Legacy data. 16. Countywide complete dataset (11 layers) was loaded to enterprise SDE

Process_Date: 20170804

Source_Information:

Source_Scale_Denominator: 2400

Type_of_Source_Media: None

Source_Citation_Abbreviation: Base Map Maintenance Services Contract, QQ-01857, 2016

Source_Contribution:

Captured and updated photogrammetric stereo models covering selected areas in the central region of Loudoun County.

Process_Step:

Process_Description:

1. Legacy PGDB converted to DWG file. 2. DWG file imported to micro station V8 and overlaid with the area to be updated. 3. New features were collected as per the data dictionary and the features that do not exist on 2017 imagery were deleted. 4. Modifications were done if there was a change in the shape and size of the features. 5. All the new and updated features were modified and coded as Update_Date= '2016. 6. Updated data was checked for edge matching. 7. DTM was modified in the update area. 8. Contours were generated, coded and edge matched with the legacy contour data. 9. Spot Elevation Points were placed. 10. All clean up tools were run. 11. Data was exported to PGDB. 12. QA/ QC Program was run and reported errors were corrected. 13. Updated data was checked against 2017 Orthos for completeness. 14. All the delivery blocks were merged into a single PGDB. 15. Updated Data was merged with the Legacy data. 16. Countywide complete dataset (11 layers) was loaded to enterprise SDE

Process_Date: 20181213

Source_Information:

Source_Citation:

Citation_Information:

Title: Base Map Maintenance Services Contract, QQ-01857, 2017

Source_Scale_Denominator: 2400

Type_of_Source_Media: none

Source_Citation_Abbreviation: Base Map Maintenance Services Contract, QQ-01857, 2017

Source_Contribution:

Captured and updated photogrammetric stereo models covering selected areas in the central region of Loudoun County.

Source_Information:

Source_Citation:

Citation_Information:

Publication_Date: 20190904

Title: Contract # - QQ-01857, 2018

Source_Scale_Denominator: 2400

Type_of_Source_Media: none

Source_Citation_Abbreviation: Base Map Maintenance Services Contract, QQ-01857, 2018

Source_Contribution:

Captured and updated photogrammetric stereo models covering selected areas in the northern region of Loudoun County.

Process_Step:

Process_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: Loudoun County, VA, OMAGI

Process_Description:

1. Legacy PGDB converted to DWG file. 2. DWG file imported to micro station V8 and overlaid with the area to be updated. 3. New features were collected as per the data dictionary and the features that do not exist on 2018 imagery were deleted. 4. Modifications were done if there was a change in the shape and size of the features. 5. All the new and updated features were modified and coded as Update_Date= '2018. 6. Updated data was checked for edge matching. 7. DTM was modified in the update area. 8. Contours were generated, coded and edge matched with the legacy contour data. 9. Spot Elevation Points were placed. 10. All clean up tools were run. 11. Data was exported to PGDB. 12. QA/ QC Program was run and reported errors were corrected. 13. Updated data was checked against 2018 Orthos for completeness. 14. All the delivery blocks were merged into a single PGDB. 15. Updated Data was merged with the Legacy data. 16. Countywide complete dataset (11 layers) was loaded to enterprise SDE

Process_Date: 20190904

Source_Information:

Source_Citation:

Citation_Information:

Publication_Date: 20210427

Title:

RFQ 108783, Agreement for Service for Base Map Maintenance Services, 2020

Source_Scale_Denominator: 2400

Type_of_Source_Media: none

Source_Citation_Abbreviation:

RFQ 108783, Agreement for Service for Base Map Maintenance Services, 2020

Source_Contribution:

Captured and updated photogrammetric stereo models covering selected areas in the Southeast region of Loudoun County.

Process_Step:

Process_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: Loudoun County, VA, OMAGI

Process_Description:

1. Legacy PGDB converted to DWG file. 2. DWG file imported to micro station V8 and overlaid with the area to be updated. 3. New features were collected as per the data dictionary and the features that do not exist on 2020 imagery were deleted. 4. Modifications were done if there was a change in the shape and size of the features. 5. All the new and updated features were modified and coded as Update_Date= '2020. 6. Updated data was checked for edge matching. 7. DTM was modified in the update area. 8. Contours were generated, coded and edge matched with the legacy contour data. 9. Spot Elevation Points were placed. 10. All clean up tools were run. 11. Data was exported to PGDB. 12. QA/ QC Program was run and reported errors were corrected. 13. Updated data was checked against 2020 Orthos for completeness. 14. All the delivery blocks were merged into a single PGDB. 15. Updated Data was merged with the Legacy data. 16. Countywide complete dataset (11 layers) was loaded to enterprise SDE

Process_Date: 20210427

Spatial_Data_Organization_Information:

Indirect_Spatial_Reference: Loudoun County

Direct_Spatial_Reference_Method: Vector

Point_and_Vector_Object_Information:

SDTS_Terms_Description:

SDTS_Point_and_Vector_Object_Type: GT-polygon composed of chains

Point_and_Vector_Object_Count: 90555

Spatial_Reference_Information:

Horizontal_Coordinate_System_Definition:

Planar:

Map_Projection:

Map_Projection_Name: Lambert Conformal Conic

Lambert_Conformal_Conic:

Standard_Parallel: 38.03333333333333

Standard_Parallel: 39.2

Longitude_of_Central_Meridian: -78.5

Latitude_of_Projection_Origin: 37.66666666666666

False_Easting: 11482916.66666666

False_Northing: 6561666.666666666

Planar_Coordinate_Information:

Planar_Coordinate_Encoding_Method: coordinate pair

Coordinate_Representation:

Abscissa_Resolution: 0.00020833333333333297

Ordinate_Resolution: 0.00020833333333333297

Geodetic_Model:

Horizontal_Datum_Name: D North American 1983 HARN

Ellipsoid_Name: GRS 1980

Semi-major_Axis: 6378137.0

Denominator_of_Flattening_Ratio: 298.257222101

Entity_and_Attribute_Information:

Detailed_Description:

Entity_Type:

Entity_Type_Label: GISDBB.GISBROW.RDCASING_POLY

Attribute:

Attribute_Label: OBJECTID

Attribute_Definition: Internal feature number.

Attribute_Definition_Source: ESRI

Attribute_Domain_Values:

Unrepresentable_Domain:

Sequential unique whole numbers that are automatically generated.

Attribute:

Attribute_Label: RD_SURFACE

Attribute_Definition: Characterization of Surface Permeability (paved or non-paved)

Attribute_Definition_Source: Loudoun County

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: See Overview Description for data dictionary

Attribute:

Attribute_Label: RD_SOURCE

Attribute_Definition: Source that created or edited feature class

Attribute_Definition_Source: Loudoun County

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: See Overview Description for data dictionary

Attribute:

Attribute_Label: RD_UPD_DATE

Attribute_Definition:

The date a feature was last re-mapped, although it may have been reviewed for changes more recently.

Attribute_Definition_Source: Loudoun County

Attribute_Domain_Values:

Unrepresentable_Domain: user generated text

Attribute:

Attribute_Label: RD_UPD_USER

Attribute_Definition:

Not for public distribution. Internal User ID of editor creating or modifying a feature. Intended to track and audit features internally by County.

Attribute_Definition_Source: Loudoun County

Attribute:

Attribute_Label: RD_TYPE

Attribute_Definition: Classification of Road Type

Attribute_Definition_Source: Loudoun County

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: See Overview Descripton for data dictionary of attribute

Attribute:

Attribute_Label: SHAPE__ST_AREA__

Attribute_Definition: Area of Road Casing feature in internal units

Attribute_Definition_Source: Loudoun County

Attribute_Domain_Values:

Unrepresentable_Domain: Positive whole numbers that are automatically generated

Attribute:

Attribute_Label: SHAPE__SDELENGTH__

Attribute_Definition: Perimeter of feature in internal units

Attribute_Definition_Source: Loudoun County

Attribute_Domain_Values:

Unrepresentable_Domain: Positive whole numbers that are automatically generated

Attribute:

Attribute_Label: SHAPE

Attribute_Definition: Feature geometry.

Attribute_Definition_Source: ESRI

Attribute_Domain_Values:

Unrepresentable_Domain: Coordinates defining the features.

Attribute:

Attribute_Label: DB2GSE.ST_Area(SHAPE)

Attribute_Definition: Area of feature in internal SDE units

Attribute_Definition_Source: Loudoun County

Attribute_Domain_Values:

Unrepresentable_Domain: Positive whole numbers that are automatically generated

Attribute:

Attribute_Label: DB2GSE.SdeLength(SHAPE)

Attribute_Definition: Perimeter of feature in SDE internal units

Attribute_Definition_Source: Loudoun County

Attribute_Domain_Values:

Unrepresentable_Domain: Positive whole numbers that are automatically generated

Overview_Description:

Entity_and_Attribute_Overview:

RD_TYPE: Designation of road type code description ---- ------------------ 1 Road 2 Parking Lots 3 Driveways 4 Airport Runways 8 W&OD Trail 9 Bridge Deck or Overpass 50 Proposed Construction from DXF plat

Entity_and_Attribute_Detail_Citation:

Feature Depiction Descriptions based on USACE publication, EM 1110-1-1000, July 31, 2002 and further developed according to Loudoun County Data Dictionary.
Road [Type = 1] Defined by edge of pavement, excluding paved shoulder or gutter. Roads include access to multiple dwellings, the distinction between roads and driveways is a driveway has access to one dwelling where a road has access to multiple driveways. Roads providing access to multifamily (apartment) or industrial buildings shall be collected from the main road to the beginning of the parking lot. Road casings shall be collected in front of shopping malls to indicate the access; a constant width shall be applied due to the lack of actual curbs or edge or road. If parking islands are present, use edge of parking island for delineation of road. Unpaved roads can be dirt or gravel but must permit travel by vehicles other than 4X4 "off-road" vehicles. If 4-wheel drive is necessary, feature classified as a "trail" in miscellaneous cultural arcs. Also primary thoroughfare of significant length into parking areas. Loudoun County Street centerline layer may be used as reference for roads. -------------------------------------------------------- Commercial Parking Over 200 ft long -for 20 spaces or more [Type = 2] Digitize edge of parking lot; show parking lot islands. Does not include ingress into lot when that thoroughfare is of significant length. -------------------------------------------------------- Driveway [Type = 3] Define by edge of pavement. Driveways only have access to individual dwellings. The distinction between roads and driveways is a driveway has access to one dwelling where a road has access to multiple driveways. -------------------------------------------------------- Runway [Type = 4] Airport pavement used for takeoff, landing, or taxiing of airplanes. "Runway" also includes helipads. -------------------------------------------------------- Washington & Old Dominion Railroad Regional Park [Type = 8] Polygonal trail feature running from Purcellville to Fairfax County boundary that includes both paved bike and criss-crossing unpaved equestiran trails. -------------------------------------------------------- Bridge Deck or Overpass [Type = 9] Structure erected over obstacle or depression. "Bridge" includes automotive bridges, railroad bridges, and viaducts (Capture footbridges in Misc. Arcs). -------------------------------------------------------- Proposed Construction (DXF) [Type = 50] Transportation features captured from digital Construction Plans (still in OMAGI development)

Overview_Description:

Entity_and_Attribute_Overview: RD_SOURCE: Source that created or edited feature class

Entity_and_Attribute_Detail_Citation:

Code Description
1 Legacy (pre 2002) 2 County 3 Contract

Overview_Description:

Entity_and_Attribute_Overview: RD_SURFACE: Permeability of road surface

Entity_and_Attribute_Detail_Citation:

Code Description
P Paved as asphalt or concrete. N Unpaved as gravel, dirt or un-improved.

Distribution_Information:

Distributor:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: Loudoun County, VA, OMAGI

Contact_Position: Public Information Counter

Contact_Address:

Address_Type: mailing and physical

Address: MS 65

Address: 1 Harrison Street SE, 2nd Floor

City: Leesburg

State_or_Province: VA

Postal_Code: 20175

Country: US

Contact_Voice_Telephone: (703)771-5778

Contact_Facsimile_Telephone: (703)771-5075

Contact_Electronic_Mail_Address: mapping@loudoun.gov

Hours_of_Service: 8:00-4:30 EST, M-F

Distribution_Liability:

Chapter 54.1-402 of the Code of Virginia. "Any determination of topography or contours, or any depiction of physical improvements, property lines or boundaries is for general information only and shall not be used for the design, modification, or construction of improvements to real property or for flood plain determination." 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.

Standard_Order_Process:

Digital_Form:

Digital_Transfer_Information:

Format_Name: DXF

Format_Specification: AutoCAD Digital Exchange File

Digital_Transfer_Option:

Offline_Option:

Offline_Media: dvd

Fees:

Loudoun County distributes spatial data in ArcGIS database or shapefile or DXF format. Selected aerial imagery is also available.

Ordering_Instructions:

Visit our website at: <http://www.loudoun.gov/omagi> and click on "Maps and Data."  Hardcopy maps may also be available. Please contact the Mapping Office Public Information Counter for more information regarding all data requests.

Metadata_Reference_Information:

Metadata_Date: 20210427

Metadata_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: Loudoun County, VA, OMAGI

Contact_Position: Base Map Coordinator

Contact_Address:

Address_Type: mailing and physical

Address: MS 65

Address: 1 Harrison Street SE, 2nd Floor

City: Leesburg

State_or_Province: VA

Postal_Code: 20175

Contact_Voice_Telephone: (703)771-5778

Contact_Facsimile_Telephone: (703)771-5075

Contact_Electronic_Mail_Address: mapping@loudoun.gov

Hours_of_Service: 8:00-4:30 EST, M-F

Metadata_Standard_Name: FGDC Content Standard for Digital Geospatial Metadata

Metadata_Standard_Version: FGDC-STD-001-1998

Metadata_Time_Convention: local time

Metadata_Use_Constraints:

This metadata reflects the source Geodatabase format and specific elements may not apply if your data is exported to SHP, DXF, or .e00 products. User must be aware that changes to data schema occur during data export that may not be reflected in this metadata, which represents Loudoun County's corporate geodatabase. Acknowledgement of Loudoun County would be appreciated in the use of this metadata.