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. This dataset is the result of combining the most recent digital shoreline inventories for Virginia.
To inventory Virginia's tidal shoreline conditions.
There are three shapefiles that are part of the Shoreline Inventory database: *_lubc, *_astru, *_sstru. The _lubc (land use and bank cover) is a linear shapefile containing data about land use, bank height, erosion, bank cover, Phragmites australis, tree fringe, canopy overhang, marsh, and beach status along the shoreline. The _sstru (shoreline structures) is a linear shapefile delineating hard structures at the shoreline (bulkhead, breakwater, dilapidated bulkhead, debris, jetty, marina, marsh toe revetment, unconventional, riprap, groin fields). The _astru (access structures) is a point shapefile with locations of docks, ramps,a dilapidated docks, outfalls, and boathouses. The attributes of these three shapefiles are explained in the Entity and Attribute Information section below.
ground condition at time of survey
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.
Greate Road
The attributes were compared to original GPS data logs for accuracy. Errors were corrected where noted.
Chain-node topology present. Linear coverages were built for lines and point coverages were built for points.
All shoreline 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.
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.
Digital shoreline serves as base shoreline for shoreline conditions for the following counties: King and Queen, King William, Middlesex, and Poquoson.
Serves as a background coverage in some of the map portfolios. Used to accurately position land use and cover data. Used to create a new digital shoreline coverage that serves as the base shoreline for shoreline conditions. Counties that used this shoreline: Accomack, Caroline, Essex, Lancaster, Northumberland, Richmond, and Pagan River. Counties that used this in conjunction with another shoreline: Gloucester, King and Queen, King George, King William, Middlesex, New Kent, Newport News, and Poquoson.
Provided the base shoreline for the City of Norfolk
Imagery (2002) serves as a background in the map portfolio. Imagery is used to update land use and structure data as well as to remotely code areas not previously surveyed in the field. The VBMP shoreline was also used and adjusted using the imagery where needed. This shoreline was used in the following counties: Gloucester, Lynnhaven Bay, Stafford, and Westmoreland.
Imagery (2007) serves as a background in the map portfolio. Imagery is used to update land use and structure data as well as to remotely code areas not previously surveyed in the field. The VBMP shoreline was also used and adjusted using the imagery where needed. This shoreline was used in the following counties: City of Chesapeake, City of Portsmouth, King George, New Kent, Newport News, and Mathews.
Data was collected by a three-person field crew (1989-2001) or a two-person field crew (2002 to present) (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.
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.
In the ArcMap environment, boat-track arcs and points were manually shifted to the base shoreline. Arcs were split and moved to locations on the shoreline perpendicular to the original locations on the boat-track. Points were also moved to locations on the shoreline perpendicular to the original locations on the boat-track. Shoreline arc segments and points were coded, and the shapefiles were visually checked for attribute accuracy between coded shoreline and boat-track data.
Land use, point structure, and linear structure locations were digitally checked and repositioned if necessary with imagery displayed in the background. 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.
County inventories were merged together.
Metadata imported.
Internal feature number.
ESRI
Feature geometry.
ESRI
erosion control
Structures parallel to the shoreline
Can include tires, tubes, rubble, etc
Structures perpendicular to the shoreline
includes infrastructure such as piers, bulkhead, wharfs. Divided into two categories (<50 slips & >50 slips) beginning in the 2003 field season.
Placed in front of an eroding marsh
Miscellaneous was divided into two categories (debris & unconventional) beginning with the 2004 field season.
Composed of non-traditional materials
Date of data capture
Data coded in the lab using background imagery
county or waterbody inventoried
year data collected
base shoreline used (refer to lineage)
Two other shapefiles combine with _lubc to complete the Shoreline Inventory. The complete set includes _lubc, _astru, and _sstru. Attributes in the _lubc file include: FEATURE or land use may contain the following values: agriculture, bare, commercial, educational/school, family dwelling, forest, grass, industrial, military, multifamily dwelling, paved, residential, scrub-shrub, and timbered; HEIGHT is the bank height with 0 - 5 feet, 5 - 10 feet, and 10 - 30 feet, and >30; EROSION or bank erosion can have the values: low, high, undercut, erosional, erosional/undercut, stable, stable/undercut, transitional, or transition/undercut; MARSH values may be yes, no, yes(erosion), yes(no_erosion), embayed, extensive, and fringe <5, 5-10, 10-15 and >15; Beach values are the presence or absence of beach where "yes" indicates a beach and "no" or a null value indicates no beach; Cover (bank cover) is defined as bare, partial, or total; Tree Fringe is coded as 'Yes" for the presence of a tree buffer along the shoreline; Canopy overhang is "yes" if the tree fringe overhangs the shoreline; and REMOTE refers to how the data was gathered: a blank value indicates the data was collected with the GPS unit, a "y" indicates that the shoreline attributes where determined from imagery. Phragmites australis is coded as 'yes' where its presence is noted. Attributes in the _astru (access structure shapefile) are: PNTSTRUC contains access structures such as boathouse, dock, dilapidated dock, outfall, and public or private ramp; and REMOTE. Attributes found in the _sstru shapefile are: STRUCTURE (erosion control)with values such as breakwater, bulkhead, debris, dilapidated bulkhead, groinfield, jetty, marina, marsh toe revetment, military wharf, miscellaneous, riprap, seawall, shipyard, unconventional, and wharf; and REMOTE.
Greate Road