The City of Alexandria Shoreline Access Structures

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Metadata:

Identification_Information:
Citation:
Citation_Information:
Originator:
Comprehensive Coastal Inventory Program, Virginia Institute of Marine Science
Publication_Date: 2010
Title: The City of Alexandria Shoreline Access Structures
Geospatial_Data_Presentation_Form: vector digital data
Online_Linkage:
<http://ccrm.vims.edu/gis_data_maps/shoreline_inventories/index.html>
Description:
Abstract:
Shoreline Situation Reports (SSR) were first generated by VIMS in the 1970's to report the condition and status of the shore lands. The SSR series were published in hardcopy on a county by county basis for each Tidewater Virginia localities. The reports were intended to assist planners, managers, and regulators in decisions pertaining to management of coastal areas and natural resources therein. This Shoreline Inventory report continues a process which updates and expands the earlier reports. Data collected reports conditions surveyed in the immediate riparian zone, the bank, and along the shoreline.
Purpose: To inventory Virginia's tidal shoreline conditions.
Supplemental_Information:
There are three shapefiles that are part of the 2010 City of Alexandria Shoreline Inventory database: alex_lubc, alex_astru, alex_sstru. Alex_lubc (land use and bank cover for the City of Alexandria) is a linear shapefile containing data about land use, tree fringe, canopy overhang, bank height, bank cover, erosion, Phragmites australis, marsh, and beach status along the shoreline. Alex__sstru (the City of Alexandria shoreline structures) is a linear shapefile delineating hard structures in place at the shoreline (bulkhead, breakwater,debris, dilapidated bulkhead, riprap, jetty, marina, marsh toe revetment, wharf, unconventional, groinfields). Alex_astru (the City of Alexandria access structures) is a point shapefile with locations of docks, ramps, dilapidated docks, outfalls and boathouses. The attributes of these three shapefiles are explained in the Entity and Attribute Information section below.
Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: 6/7/2010
Currentness_Reference: ground condition at time of publication
Status:
Progress: Complete
Maintenance_and_Update_Frequency: None planned
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -77.050165
East_Bounding_Coordinate: -77.037695
North_Bounding_Coordinate: 38.833300
South_Bounding_Coordinate: 38.790687
Keywords:
Theme:
Theme_Keyword: Shoreline conditions
Theme_Keyword: Shoreline inventory
Theme_Keyword: Shoreline structures
Theme_Keyword: Access structures
Place:
Place_Keyword: Potomac River
Place_Keyword: Occoquan Bay
Place_Keyword: Pohick Bay
Place_Keyword: Accotink Bay
Place_Keyword: Hunting Creek
Place_Keyword: Little Hunting Creek
Access_Constraints: none
Use_Constraints:
These data should not be used for jurisdictional permit determinations beyond providing general shoreline condition or status information. These data have not been surveyed to property boundaries.
Point_of_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Marcia Berman
Contact_Organization: Virginia Institute of Marine Science
Contact_Position: Director of Comprehensive Coastal Inventory Program
Contact_Address:
Address_Type: mailing and physical address
Address: P.O.Box 1346 Greate Road
City: Gloucester Point
State_or_Province: VA
Postal_Code: 23061
Country: USA
Contact_Voice_Telephone: 804-684-7188
Contact_Facsimile_Telephone: 804-684-7179
Contact_Electronic_Mail_Address: marcia@vims.edu
Native_Data_Set_Environment:
Microsoft Windows Vista Version 6.1 (Build 7601) Service Pack 1; ESRI ArcCatalog 9.3.1.3000
Data_Quality_Information:
Logical_Consistency_Report:
Chain-node topology present. Linear coverages were built for lines and point coverages were built for points.
Completeness_Report:
All shoreline for the City of Alexandria that has a minimum depth of 2 feet at mean low water was surveyed. Some shorelines are coded remotely if access was restricted due to depth at time of survey. Upper reaches of creeks were often coded remotely.
Positional_Accuracy:
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
Shoreline structures were recorded with a GPS unit as the boat moved along the shoreline. Data was transferred from the GPS boat track to an existing digital shoreline coverage by projecting data to the shoreline at a 90 degree angle from the boat track. Rectified digital orthophoto quads were used as a background coverage to aid in data positioning. Dock and boathouse point data were aligned with docks on the images. Land use features were placed along the shore so changes in land use were coincident with changes illustrated in the imagery. Positional accuracy for data that has been corrected with imagery is .3 meters (equivalent to image resolution). Data not visable on the imagery (bulkheads, riprap, etc.) has a positional accuracy of 11 meters. Accuracy was determined by comparing digitally processed data locations to onsite GPS ground surveys collected at random.
Lineage:
Source_Information:
Source_Citation:
Citation_Information:
Originator: Virginia Information Technologies Agency (VITA)
Publication_Date: 2010
Title: Virginia Base Mapping Program (VBMP) 2009
Publication_Information:
Publication_Place: Chester,VA
Publisher: Virginia Information Technologies Agency (VITA)
Process_Step:
Process_Description:
Data was collected by a two-person field crew (one person collecting land use and bank condition data and one boat operator also collecting shoreline features) using two hand-held Trimble GeoExplorers GPS Units, while navigating along the shoreline. A data dictionary designed for the inventory was installed on each GPS Unit. One data collector records natural features including land use, bank height, presence of marsh or beach, and shoreline stability. A second person collects data on the hardened structures: riprap, bulkheads, docks, boatramps, etc. Point features (docks, boathouses, ramps) were surveyed with a six second observation recorded at 1 reading/second. Linear features were surveyed kinematically at a rate of one observation every 3 seconds.
Process_Step:
Process_Description:
Data from the GPS units were postprocessed on a PC with Trimble Pathfinder Office software. Postprocessing includes differential correction using base station data collected at the VIMS laboratory. Corrected data is converted to shapefiles for further processing.
Process_Step:
Process_Description:
In the ArcMap environment, boat-track arcs were manually shifted to the base shoreline (VBMP). Arcs were split and moved to locations on the shoreline perpendicular to the original locations on the boat-track. Shoreline arc segments were coded, and the shapefiles were visually checked for attribute accuracy between coded shoreline and boat-track data.
Process_Step:
Process_Description:
In ArcMap, boat-track points were manually shifted to the base shoreline (VBMP). Points were moved to locations on the shoreline perpendicular to the original locations on the boat-track. Points were coded and the access structure (astru) was visually checked for attribute accuracy between coded shoreline and boat-track data.
Process_Step:
Process_Description:
Land use, dock, and boathouse locations were digitally checked and repositioned if necessary with VBMP imagery displayed as a background coverage. This was done using ArcMap capabilities. Areas inaccessible by boat due to low tide were coded based on features observed on the imagery. The "remote" coded areas were given the item REMOTE = "yes" to distinquish them from GPS collected data.
Process_Step:
Process_Description:
A portfolio was created for the City of Alexandria. Each plate shows four maps: riparian land use, bank conditions, shoreline features, and natural buffers. VBMP (2009) Infrared WGS imagery is displayed in the background to provide users with additional information.
Spatial_Data_Organization_Information:
Direct_Spatial_Reference_Method: Vector
Point_and_Vector_Object_Information:
SDTS_Terms_Description:
SDTS_Point_and_Vector_Object_Type: Entity point
Point_and_Vector_Object_Count: 26
Spatial_Reference_Information:
Horizontal_Coordinate_System_Definition:
Planar:
Grid_Coordinate_System:
Grid_Coordinate_System_Name: Universal Transverse Mercator
Universal_Transverse_Mercator:
UTM_Zone_Number: 18
Transverse_Mercator:
Scale_Factor_at_Central_Meridian: 0.999600
Longitude_of_Central_Meridian: -75.000000
Latitude_of_Projection_Origin: 0.000000
False_Easting: 500000.000000
False_Northing: 0.000000
Planar_Coordinate_Information:
Planar_Coordinate_Encoding_Method: coordinate pair
Coordinate_Representation:
Abscissa_Resolution: 0.000000
Ordinate_Resolution: 0.000000
Planar_Distance_Units: meters
Geodetic_Model:
Horizontal_Datum_Name: North American Datum of 1983
Ellipsoid_Name: Geodetic Reference System 80
Semi-major_Axis: 6378137.000000
Denominator_of_Flattening_Ratio: 298.257222
Entity_and_Attribute_Information:
Detailed_Description:
Entity_Type:
Entity_Type_Label: alex_astru
Attribute:
Attribute_Label: FID
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: Shape
Attribute_Definition: Feature geometry.
Attribute_Definition_Source: ESRI
Attribute_Domain_Values:
Unrepresentable_Domain: Coordinates defining the features.
Attribute:
Attribute_Label: GPS_Date
Attribute_Definition: Date of survey
Attribute:
Attribute_Label: Feat_Name
Attribute_Definition: Type of access structure
Attribute:
Attribute_Label: remark
Attribute_Definition: any comments
Attribute:
Attribute_Label: Ownership
Attribute_Definition: For ramps: Private or Public
Attribute:
Attribute_Label: REMOTE
Attribute_Definition: remotely coded in lab
Attribute:
Attribute_Label: PNTSTRUC
Attribute_Definition: Type of access structure
Distribution_Information:
Resource_Description: Downloadable Data
Distribution_Liability:
The Comprehensive Coastal Inventory Program (CCI) at VIMS performs a service by distributing data generated by either CCI or public agencies which offer data without restriction or charge. CCI assumes no responsibility for data accuracy or precision, metadata completeness or correctness for digital information. CCI assumes no liability for misuse of any data which may arise as a result of any alteration, conversion, or combination with other data sources. As well, the timeliness and scale of these products must be considered when evaluating appropriate use.
Standard_Order_Process:
Digital_Form:
Digital_Transfer_Information:
Transfer_Size: 0.001
Metadata_Reference_Information:
Metadata_Date: 20130228
Metadata_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Sharon Killeen
Contact_Organization: Comprehensive Coastal Inventory Program
Contact_Position: GIS Programmer/Analyst
Contact_Address:
Address_Type: mailing and physical address
Address: P.O.Box 1346 Greate Road
City: Gloucester Point
State_or_Province: VA
Postal_Code: 23062
Country: USA
Contact_Voice_Telephone: 804-684-7534.
Contact_Facsimile_Telephone: 804-684-7179
Contact_Electronic_Mail_Address: sharon@vims.edu
Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata
Metadata_Standard_Version: FGDC-STD-001-1998
Metadata_Time_Convention: local time
Metadata_Extensions:
Online_Linkage: <http://www.esri.com/metadata/esriprof80.html>
Profile_Name: ESRI Metadata Profile
Generated by mp version 2.9.6 on Thu Feb 28 12:21:41 2013