January, 2004 Ocean City Inlet Tidal Delta Bathymetry Grid

Metadata:


Identification_Information:
Citation:
Citation_Information:
Originator: Assateague Island National Seashore
Publication_Date: Unpublished Material
Publication_Time: Unknown
Title:
January, 2004 Ocean City Inlet Tidal Delta Bathymetry Grid
Edition: First edition
Geospatial_Data_Presentation_Form: raster digital data
Online_Linkage: http://science.nature.nps.gov/nrdata
Larger_Work_Citation:
Citation_Information:
Publication_Date: Unknown
Geospatial_Data_Presentation_Form: tabular digital data
Description:
Abstract:
As part of the Assateague Island National Seashore (ASIS) North End Restoration Project, sediment is being dredged from the Ocean City tidal delta complex, and deposited in the near shore of Assateague Island. These bathymetry grid datasets are a result of bathymetery measurements taken by the US Army Corps of Engineers, then interpolated to form a grid that can be easily used by researchers and managers working on this project. These bathymetry datasets are collected before and after each dredge event. Please see the 'Purpose' section to see which event this dataset does pertain. Prior permission must be granted from Gregory Bass of the US Army Corps of Engineers, Baltimore District, before this data is distributed.
Purpose:
To portray the bathymetry of sections of the Ocean City tidal delta complex. This particular dataset is the first bathymetry survey collected, spanning the entire ebb tidal delta, inlet, and portions of the flood tidal delta. It is also used as a pre-dredge dataset to the dredging events that took place from January 31 through February 13, 2004. This data set was used as a predredge survey for the Ocean City, Maryland Inlet. The dredge event took place from 20040130 - 20040401. There is also a post-dredge survey which was collected from 20040415 - 20040417.
Supplemental_Information:
This dataset is part of a series of bathymetry grids. The ASIS North End Restoration Project Timeline PDF also contains detailed information on dates of dredge events.
Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 20040113
Ending_Date: 20040124
Currentness_Reference:
ground condition
Status:
Progress: Complete
Maintenance_and_Update_Frequency: Unknown
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -75.107170
East_Bounding_Coordinate: -75.064408
North_Bounding_Coordinate: 38.333803
South_Bounding_Coordinate: 38.302976
Keywords:
Theme:
Theme_Keyword_Thesaurus: Assateague Island National Seashore Keyword Thesaurus
Theme_Keyword: bathymetry
Theme_Keyword: beach nourishment
Theme_Keyword: beach dynamics
Theme_Keyword: geomorphology
Theme_Keyword: jetties & groins
Theme_Keyword: sediment (marine)
Theme:
Theme_Keyword_Thesaurus: National Park Service Theme Category Thesaurus
Theme_Keyword: Geology
Theme_Keyword: Elevation / Bathymetry
Theme:
Theme_Keyword_Thesaurus: ISO 19115 Topic Category
Theme_Keyword: elevation
Place:
Place_Keyword_Thesaurus: Geographic Names Information System
Place_Keyword: North America
Place_Keyword: Maryland
Place_Keyword: Worcester County
Place_Keyword: Assateague Island National Seashore
Place_Keyword: North End
Place:
Place_Keyword_Thesaurus: National Park System Unit Name Thesaurus
Place_Keyword: Assateague Island National Seashore
Place:
Place_Keyword_Thesaurus: National Park System Unit Code Thesaurus
Place_Keyword: ASIS
Access_Constraints: Not to be distributed outside of ASIS.
Use_Constraints:
Not to be used by anyone not associated with ASIS or the US Army Corps of Engineers.
Point_of_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: Assateague Island National Seashore
Contact_Position: GIS Specialist
Contact_Address:
Address_Type: mailing and physical address
Address:
7206 National Seashore Lane
City: Berlin
State_or_Province: MD
Postal_Code: 21811
Country: USA
Contact_Voice_Telephone: 410-641-1443
Contact_Facsimile_Telephone: 410-641-1099
Contact_Electronic_Mail_Address: asis_gis@nps.gov
Hours_of_Service: Mon - Fri, 9:00am - 4:00pm
Data_Set_Credit:
Geodynamics LLC, ASIS
Security_Information:
Security_Classification_System: Data is considered classified
Security_Classification: Restricted
Security_Handling_Description: Please contact Courtney Schupp
Native_Data_Set_Environment:
Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.1.0.722
Cross_Reference:
Citation_Information:
Originator: Assateague Island National Seashore
Publication_Date: Unpublished Material
Title:
Metadata for January, 2004 Ocean City Inlet Tidal Delta Bathymetry Grid
Geospatial_Data_Presentation_Form: raster digital data
Online_Linkage: http://nrdata.nps.gov/ASIS/ASISdata/octd_2004_2006.xml
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Data_Quality_Information:
Attribute_Accuracy:
Attribute_Accuracy_Report:
This is an interpolated dataset, and accuracy assessments have not been performed on it.  The accuracy report from the source data is as follows:

Position Accuracy Information: Horizontal and Vertical Accuracy Report from Geodetic GPS Site Calibration:

A detailed geodetic GPS site calibration was performed (January 12, 2004) prior to the start of the multibeam data acquisition. The site calibration is used to determine the base station quality and analyze any potential spatial separations between the local geoid heights (GEOID 99) and ellipsoidal values (WGS-84) that may influence the resultant orthometric elevations. The calibration entails selecting the control to be used for the RTK-GPS base station receiver and radio broadcast system and checking at least 3 known geodetic benchmarks of exceptional horizontal and vertical quality within and even outside the survey boundaries. The benchmarks are occupied in "control point mode" over 300 epochs or approximately 3 to 5 minutes. Detailed results of the site calibration can be found in a separate directory on this CD labeled "Supplemental_QA_QC_Info"; however, the average horizontal difference in the Easting was 6.9 cm and the average difference in the Northing was 7.4 cm. The average measured divergence in the vertical was 7.8 mm.
Logical_Consistency_Report:
No accuracy tests have been performed on these grid datasets.  The logical consistency report for the original source data is as follows:

The minimum standards for multibeam echo sounder sonar system resolution are set forth in the NOS Hydrographic Surveys, Specifications and Deliverables, and the USACE Hydrographic Survey Manual. Geodynamics maintains and operates the Simrad EM3000 Multibeam system from data acquisition to processing, such that the system can detect shoals that measure 2m x 2m horizontally and 1m vertically in depths of 40m or less. For depths greater than 40m the minimum size of detectable targets shall be 10% of the depth horizontal dimension and 5% of the depth for vertical dimensions.
Completeness_Report:
These grid datasets contain all points provided to ASIS for each survey.  An example of a completeness report from the original source data is as follows:

Multibeam survey data collected for the USACE Baltimore District at Ocean City, Maryland in January 2004 have undergone rigorous field and processing standards in accordance with the USACE Hydrographic Survey Manual (2003) and the NOS Hydrographic Surveys, Specifications and Deliverables Manual (2003). The survey data described in the following metadata is complete and adequate for modeling and charting purposes.
Positional_Accuracy:
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
Data is interpolated from source dataset.  Source data had an average horizontal accuracy of 6.9cm.
Quantitative_Horizontal_Positional_Accuracy_Assessment:
Horizontal_Positional_Accuracy_Value: 6.9 cm
Horizontal_Positional_Accuracy_Explanation:
see accuracy report
Vertical_Positional_Accuracy:
Vertical_Positional_Accuracy_Report:
Data is interpolated from source dataset.  Source data had an average vertical accuracy of 7.8mm.
Quantitative_Vertical_Positional_Accuracy_Assessment:
Vertical_Positional_Accuracy_Value: 7.8 mm
Vertical_Positional_Accuracy_Explanation:
see accuracy report
Lineage:
Source_Information:
Source_Citation:
Citation_Information:
Originator: Geodynamics LLC: Geologic Oceanographic Services
Publication_Date: 20040119
Publication_Time: Unknown
Title:
High-Resolution Multibeam Swath Bathymetry Survey: Ocean City Inlet, Maryland January 2004
Edition: First Edition
Geospatial_Data_Presentation_Form: document
Online_Linkage: none
Source_Scale_Denominator: n/a
Type_of_Source_Media: ftp text file/table of coordinates
Source_Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 20040113
Ending_Date: 20040124
Source_Currentness_Reference:
ground condition
Source_Citation_Abbreviation:
.txt
Source_Contribution:
Source data of locations and bathymetry were used to create this interpolated grid.
Process_Step:
Process_Description:
Process description from the source data metadata:

The multibeam collects swath widths approximately 3.5 to 4 times the water depth. The portions of swath, mainly in the outer beams that exhibit areas of inconsistent data are clipped and not included in the final digital file. Sounding track lines are generally parallel to each other and parallel to the contour. Sinuous lines and data acquired during turns are not included in the final processed data. To meet accuracy and resolution standards for measured depths specified in the USACE Hydrographic Surveying Manual and the NOS Hydrographic Surveys, Specifications and Deliverables Manual, measured echo sounder depths were corrected for all departures from true depths attributable to the method of sounding or to faults in the measuring apparatus. These corrections are subdivided into five categories, and are listed below in the sequence in which they were applied to the data.
1. Instrument error corrections: account for the sources of error related to the sounding equipment itself.

2. Draft corrections: were added to the observed soundings to account for the depth of the echo sounder below the water surface.

3. Velocity of sound correctors: were applied to the soundings to compensate for the fact that echo sounders may only display depths based on an assumed sound velocity profile while the true velocity may vary in time and space.

4. Heave, pitch, roll, heading and navigation latency corrections: were applied to the multibeam soundings to correct for the effect of vessel motion caused by waves and swells, the error in the vessel's heading, and the time delay from the moment the position is measured until the data is received by the GPS receiver.

5. Tidal corrections: were made spatially along the survey and are tagged with each sonar ping using Real-Time Kinematic GPS systems. RTK tides were compared to observed data within the Ocean City Inlet basin. Verified NOAA tides were not available at the time of QA/QC documentation.

Multibeam Data Processing Steps in TEI software: -Data undergoes cleaning or snipping of bad or spiky pings in ISIS (if necessary) -Data files (XTF) are imported into Bathy Pro. -Map Settings (projection and resolutions) -Sensor Geometry (applies the static adjustments/offsets determined in the patch test to the data) -Data are filtered for bad pings, excessive speed and spikes in Bathy Pro -Tide File (RTK or Regular is applied) -Sound Velocity is applied -Fill Gaps and Smoothing filters may be applied -Generate isocurves and/or soundings.
Process_Date: 200401
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: David Bernstein
Contact_Organization: Geodynamics
Contact_Position: Geologist & Mapping Specialist
Contact_Voice_Telephone: 843-997-9111
Contact_Electronic_Mail_Address: dave@geodynamicsgroup.com
Hours_of_Service: 6:30am to 8:00pm
Process_Step:
Process_Description:
Data was sent to ASIS as a text file of x and y locations, with bathymetry.  Rosters were then created from these  XYZ points, which were obtained by a contractor for the USACE.  The January 2004 dataset was divided into three sections (north, south, and inlet) using polygons to select the location areas; this process reduced file size and improved processing speed.

Points files were converted from MD state plane, NGVD29, feet into NAVD88, UTM, meters, using CorpsCon 5.11.08.  Points were brought into ArcMap using 'Add XY Data' Tool and were then exported as shapefiles.  To convert the depths (initially positive, meters) into depth (cm) below the surface, the field calculator was used to compute a new column, depth = elevation *-100.

To create a raster from the points shapefile,  Spatial Analyst -> Interpolate to Raster -> Kriging option was used.  Z value field was set to the negative depth in centimeters.  Other option settings were ordinary Kriging method with spherical semivariogram model and variable search radius type, 12 points.  Output cell size was 3 (meters).

Both the analysis mask and the extent were set to the same as the points shapefile.  When this did not mask the area appropriately, the mask and extent were re-set, and the raster calculator was used to multiply the new unmasked raster by 1.

Final rasters were then converted into an integer grid, so as to reduce file sizes (elevation is in centimeters.)
Process_Date: 200510
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: Assateague Island National Seashore
Contact_Position: GIS Specialist
Contact_Address:
Address_Type: mailing and physical address
Address:
7206 National Seashore Lane
City: Berlin
State_or_Province: MD
Postal_Code: 21811
Country: USA
Contact_Voice_Telephone: 410-641-1443
Contact_Facsimile_Telephone: 410-641-1099
Contact_Electronic_Mail_Address: asis_gis@nps.gov
Hours_of_Service: Mon - Fri 8:00am - 4:00pm
Process_Step:
Process_Description:
Dataset copied.
Source_Used_Citation_Abbreviation:
C:\Documents and Settings\nick villa\Desktop\Metadata_Edits\Geomorphology\northend_restoration\OC_TidalDelta_bathymetry\octd_200401
Process_Step:
Process_Description:
Dataset copied.
Source_Used_Citation_Abbreviation:
S:\Scratch\nick_temp\Metadata_Edits\octd_2004_2006\octd_200401
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Spatial_Data_Organization_Information:
Direct_Spatial_Reference_Method: Raster
Raster_Object_Information:
Raster_Object_Type: Grid Cell
Row_Count: 1139
Column_Count: 1245
Vertical_Count: 1
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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: row and column
Coordinate_Representation:
Abscissa_Resolution: 3.000000
Ordinate_Resolution: 3.000000
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
Vertical_Coordinate_System_Definition:
Altitude_System_Definition:
Altitude_Datum_Name: North American Vertical Datum of 1988
Altitude_Resolution: 1 cm
Altitude_Distance_Units: centimeters
Altitude_Encoding_Method: Explicit depth coordinate included with horizontal coordinates
Depth_System_Definition:
Depth_Datum_Name: Local surface
Depth_Resolution: 1 cm
Depth_Distance_Units: centimeters
Depth_Encoding_Method: Explicit depth coordinate included with horizontal coordinates
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Entity_and_Attribute_Information:
Detailed_Description:
Entity_Type:
Entity_Type_Label: octd_200401
Entity_Type_Definition:
Attribute table for OC Tidal Delta Bathymetry Grid
Entity_Type_Definition_Source:
ASIS
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: Value
Attribute_Definition:
bathymetry in centimeters
Attribute_Definition_Source:
ASIS
Attribute_Domain_Values:
Unrepresentable_Domain:
Bathymetry depth in centimeters.
Attribute_Value_Accuracy_Information:
Attribute_Value_Accuracy: unknown
Attribute_Value_Accuracy_Explanation:
source data is 7.8mm, unknown how the interpolation affects this value
Attribute:
Attribute_Label: Count
Attribute_Definition:
Number of cells with the corresponding bathymetry.
Attribute_Definition_Source:
ASIS
Attribute_Domain_Values:
Unrepresentable_Domain:
Whole numbers that are automatically generated representing number of cells with corresponding bathymetry.
Attribute_Value_Accuracy_Information:
Attribute_Value_Accuracy: n/a
Attribute_Value_Accuracy_Explanation:
n/a
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Distribution_Information:
Distributor:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: Assateague Island National Seashore
Contact_Position: GIS Specialist
Contact_Address:
Address_Type: mailing and physical address
Address:
7206 National Seashore Lane
City: Berlin
State_or_Province: Maryland
Postal_Code: 21811
Country: USA
Contact_Voice_Telephone: 410-641-1443
Contact_Facsimile_Telephone: 410-641-1099
Contact_Electronic_Mail_Address: asis_gis@nps.gov
Hours_of_Service: Mon - Fri 8:00am - 4:00pm
Resource_Description: Downloadable Data
Distribution_Liability:
The National Park Service shall not be held liable for improper or incorrect use of the data described and/or contained herein. These data and related graphics (i.e. GIF or JPG format files) are not legal documents and are not intended to be used as such. The information contained in these data is dynamic and may change over time. The data are not better than the original sources from which they were derived. It is the responsibility of the data user to use the data appropriately and consistent within the limitations of geospatial data in general and these data in particular. The related graphics are intended to aid the data user in acquiring relevant data; it is not appropriate to use the related graphics as data. The National Park Service gives no warranty, expressed or implied, as to the accuracy, reliability, or completeness of these data. It is strongly recommended that these data are directly acquired from an NPS server and not indirectly through other sources which may have changed the data in some way. Although these data have been processed successfully on computer systems at the National Park Service, no warranty expressed or implied is made regarding the utility of the data on other systems for general or scientific purposes, nor shall the act of distribution constitute any such warranty. This disclaimer applies both to individual use of the data and aggregate use with other data.
Standard_Order_Process:
Fees: None
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Metadata_Reference_Information:
Metadata_Date: 20061005
Metadata_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: Assateague Island National Seashore
Contact_Position: GIS Specialist
Contact_Address:
Address_Type: mailing and physical address
Address:
7206 National Seashore Lane
City: Berlin
State_or_Province: MD
Postal_Code: 21811
Country: USA
Contact_Voice_Telephone: 410-641-1443
Contact_Facsimile_Telephone: 410-641-1099
Contact_Electronic_Mail_Address: asis_gis@nps.gov
Hours_of_Service: Mon - Fri 8:00am - 4:00pm
Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata
Metadata_Standard_Version: FGDC-STD-001-1998
Metadata_Time_Convention: local time
Metadata_Access_Constraints: none
Metadata_Use_Constraints:
none
Metadata_Security_Information:
Metadata_Security_Classification: Unclassified
Metadata_Extensions:
Online_Linkage: <http://www.esri.com/metadata/esriprof80.html>
Profile_Name: ESRI Metadata Profile
Metadata_Extensions:
Online_Linkage: http://nrdata.nps.gov/profiles/nps_profile.xml
Profile_Name: NPS Metadata Profile
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