20220623
19472700
1.0
FGDC CSDGM Metadata
FALSE
CB_SAVHabitat_10yrs_wm
-8623265.179800
-8356581.182600
4423291.785500
4810611.178400
1
17.395
002
Projected
GCS_WGS_1984
Linear Unit: Meter (1.000000)
WGS_1984_Web_Mercator_Auxiliary_Sphere
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Virginia Institute of Marine Science
SAV Data Administrator
Rt. 1208 Greate Rd.
Gloucester Point
VA
32061
savadmin@vims.edu
USA
804/684-7088
ArcGIS Metadata
1.0
http://www.vims.edu/bio/sav
17.395
File Geodatabase Feature Class
<DIV STYLE="text-align:Left;"><DIV><DIV><P><SPAN>The 2011 Chesapeake Bay SAV Coverage was mapped from 1:24,000 black and white aerial photography to assess water quality in the Bay. Each area of SAV was interpreted from the rectified photography and classified into one of four density classes by the percentage of cover. The SAV beds were entered into an SDE GIS fetaure class using the quality control procedures documented below. The dataset contains all SAV areas that were identified from the areas flown. Some areas that are presumed to contain no SAV were not flown. Some small beds, particularly along narrow tributaries may not have been distinguishable on the aerial photography.</SPAN></P><P><SPAN>The Chesapeake Bay SAV Coverage was mapped from digital multispectral imagery with a 25cm GSD to assess water quality in the Bay. Each area of SAV was interpreted from the rectified imagery and classified into one of four density classes by the percentage of cover. Some small beds, particularly along narrow tributaries may not have been distinguishable on the aerial photography. Ten years of SAV data where SAV density was greater than 0 were combined to form overlapping SAV polygons. These polygons represent the density of SAV during each year of a ten year period from 2015 to 2024. </SPAN></P><P><SPAN /></P></DIV></DIV></DIV>
SAV Habitat represents the area where Submerged Aquatic Vegetation (SAV) presence was surveyed at least once during a ten year period from 2015 to 2024.
SAV Ecology, Monitoring, & Restoration Program, Virginia Institute of Marine Science
Virginia Institute of Marine Science
SAV Data Administrator
804/684-7088
Rt. 1208, Greate RD
Gloucester Point
VA
23062
US
savadmin@vims.edu
U.S. Department of Commerce, 1977, Countries, dependencies, areas of special sovereignty, and their principal administrative divisions (Federal Information Processing Standard 10-3):Washington, D.C., National Institute of Standards and Technology.
US
U.S. Department of Commerce, 1987, Codes for the identification of the States, the District of Columbia and the outlying areas of The United States, and associated areas (Federal Information Processing Standard 5-2):Washington ,D. C., National Institute of Standards and Technology.
10
51
24
U.S. Postal State Abbreviations
DE
MD
VA
Chesapeake Bay
Chincoteague Bay
SAV
vegetative surface cover
submerged aquatic vegetation
Chesapeake Bay
DE
MD
10
SAV
51
vegetative surface cover
Chincoteague Bay
VA
submerged aquatic vegetation
US
24
Access constraints: None
None
<DIV STYLE="text-align:Left;"><DIV><DIV><P><SPAN>None</SPAN></P></DIV></DIV></DIV>
Access constraints: None
None
ground condition
2011-05-21T00:00:00
2011-12-02T00:00:00
2015 to 2024 Chesapeake Bay SAV Habitat
2012-04-19T00:00:00
2012-10-31T00:00:00
2012-10-31T00:00:00
Virginia Institute of Marine Science
Rt. 1208 Greate RD
Gloucester Point
VA
23062
savadmin@vims.edu
USA
804/684-7088
Version 6.2 (Build 9200) ; Esri ArcGIS 10.6.1.9270
1
-77.464109
-75.068446
39.618179
36.886454
None
2011 SAV Aerial photography
9x9 inch b&w negatives
5/21/2011 - 12/02/2011
24000
2011 SAV Aerial photography
Airphotographics Inc
2115 Kelly Island Road
Martinsburg
WV
25405
info@airphotographics.com
USA
(800) 624-8993
(304) 267-0918
2011-12-02T00:00:00
2011-12-02T00:00:00
2011 SAV Orthophoto Mosaics
5/21/2011 - 12/02/2011
24000
2011 SAV Orthophoto Mosaics
2012-03-15T00:00:00
2012-03-15T00:00:00
2012-11-23T00:00:00
Virginia Institute of Marine Science
State boundaries adjusted to include shore areas
State boundaries adjusted to include shore areas
20081006
20081006
Virginia Instute of Marine Science
New 2004 Chesapeake Bay Program Segments adjusted to include land areas
New 2004 Chesapeake Bay Program Segments adjusted to include land areas
20081006
20081006
Virginia Institute of Marine Science
The SAV beds are interpreted on-screen from the orthophoto mosaics using ESRI ArcInfo GIS software. The identification and delineation of SAV beds by photo interpretation utilizes all available information including: knowledge of aquatic grass signatures on film, distribution of SAV in 2011 from aerial photography, 2011 ground survey information, and aerial site surveys.
In addition to delineating SAV bed boundaries, an estimate of SAV density within each bed was made by visually comparing each bed to an enlarged crown density scale similar to those developed for estimating crown cover of forest trees from aerial photography (Paine, 1981). Bed density was categorized into one of four classes based on a subjective comparison with the density scale. These were: 1, very sparse (<10% coverage); 2, sparse (10-40%); 3, moderate (40-70%); or 4, dense (70-100%). Either the entire bed or subsections within the bed were assigned a bed density number (1 to 4) corresponding to the above density classes. Some beds were subsectioned to delineate variations of SAV density. Additionally, each distinct SAV bed or bed subsection was assigned an identifying one or two letter designation unique to its map. Coupled with the appropriate SAV quadrangle number and year of photography, these letter designations uniquely identify each SAV bed in the database.
2011-03-15T00:00:00
Scanned aerial photography negatives are georectified and orthographically corrected to produce a seamless series of aerial mosaics following the standard operating procedures (SOP). ERDAS IMAGINE Leica Photogrammetry Suite (LPS) image processing software is used to orthographically correct the individual flight lines using a bundle block solution. Camera lens calibration data is matched to the image location of fiducial points to define the interior camera model. Control points from USGS DOQQ images and National Agriculture Imagery Program (NAIP) imagery provide the exterior control, which is enhanced by a large number of image-matching tie points produced automatically by the software when IMU data were not available. The exterior and interior models are combined with a 30-meter resolution digital elevation model (DEM) from the USGS National Elevation Dataset (NED) to produce an orthophoto for each aerial photograph.
The orthophotographs that cover each USGS 7.5 minute quadrangle area are adjusted to approximately uniform brightness and contrast and are mosaicked together using the ERDAS Imagine mosaic tool, producing a one-meter resolution quad-sized mosaic.
2012-03-15T00:00:00
The bay segments were overlayed on the dataset by VIMS staff, dividing any beds that fell into multiple segments.
2012-03-15T00:00:00
he state boundaries were overlayed on the dataset by VIMS staff, dividing any beds that fell into multiple states.
2012-03-15T00:00:00
The density attribute for all beds has been reviewed by an experienced photo-interpreter for correctness and consistency with analysis for prior years.
Horizontal positional accuracy is based upon orthorectification of scanned aerial photography using USGS digital orthothophoto quadrangles for horizontal control and USGS 30m DEM data as vertical control. Horizontal RMSE for individual flightlines was held to less than four meters.
The GIS data has been cross-checked against data tables and ground observations.
The dataset contains all SAV areas that were identified from the areas flown. Some areas that are presumed to contain no SAV were not flown. Some small beds, particularly along narrow tributaries may not have been distinguishable on the aerial photography. While the entire Bay was flown, some portions of the Bay were not mapped since SAV signatures were masked by excess turbidity present months after the passage of Hurricane Irene and Tropical Storm Lee. The regions that were not mapped are contained within nine CBP segments, including the Middle, Upper and Western Branch of the Patuxent River; the Middle and Upper Potomac River; Piscataway Creek; and the Anacostia River. These regions had 2,183 ha of SAV in 2010 (5,393 ac, 7% of the 2010 total).
EPSG
8.8(9.3.1.2)
CB_SAVHabitat_10yrs_wm
Feature Class
4679
VIMS
VIMS - SAV Program
OBJECTID
OBJECTID
OID
4
0
0
Internal feature number.
Esri
Sequential unique whole numbers that are automatically generated.
SHAPE
Shape
Geometry
0
0
0
Feature geometry.
ESRI
Coordinates defining the features.
ST
ST
String
2
0
0
U.S. State which contains the SAV bed
US State Abbreviations
DC
Washington DC
State Abbreviations
DE
Delaware
State Abbreviations
VA
Virginia
State Abbreviations
MD
Maryland
State Abbreviations
SAVHabitat
SAVHabitat
String
255
0
0
YearRange
YearRange
String
255
0
0
SHAPE_Area
Shape_Area
Double
8
0
0
Area of feature in internal units squared.
ESRI
Positive real numbers that are automatically generated.
Shape_Length
Shape_Length
Double
8
0
0
Length of feature in internal units.
Esri
Positive real numbers that are automatically generated.
dataset
4679
Simple
FALSE
4679
TRUE
FALSE
20260227