Hudson River Estuary 100 KHz sidescan mosaics 2-meter resolution

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: Lamont-Doherty Earth Observatory of Columbia University

Publication_Date: 2005

Title:

Hudson River Estuary 100 KHz sidescan mosaics 2-meter resolution

Geospatial_Data_Presentation_Form: remote-sensing image

Series_Information:

Series_Name: Hudson River Estuary Program

Issue_Identification: benthic mapping project

Publication_Information:

Publication_Place: Albany, NY

Publisher: NYS DEC

Description:

Abstract:

Images of the estuary floor derived from sidescan data are mosaiced to provide a 2-dimensional image of the estuary floor.

Purpose:

In 1996, the New York State Department of Environmental Conservation (DEC) initiated an effort to map the benthic habitat of the Hudson River Estuary as part of a larger Hudson River Action Plan. This project includes extensive mapping using sidescan sonar, subbottom profiling, single and multi-beam bathymetry, as well as collecting ground truth data with sediment cores, grab samples, and sediment profiling imagery (SPI). The goal of the project is the creation of a comprehensive data set that includes detailed interpretive maps of sediment distribution, grain size, bed forms, and benthic habitats

Supplemental_Information:

Peer Reviewed Publications
- Bell, R.E. et al., 2006, Benthic habitat mapping in the Hudson River Estuary, in J. Levinton and J. Waldman(editors), The Hudson River Estuary, Cambridge Univ Press., pp 51-64.
- Carbotte et al., 2004, Environmental change and oyster colonization within the Hudson River estuary linked to Holocene climate, Geo-Marine Letters, 24, 212-224.
- McHugh et al., 2004, Spatial variations in a condensed interval between estuarine and open marine settings: Holocene Hudson River Estuary and adjacent continental shelf, Geology, 32 (2): 169-172.
- Nitsche et al., 2004, Process-related classification of acoustic data from the Hudson River Estuary, Marine Geology, 209(1-4): 131-145.
- Nitsche et al., 2005, Integrative acoustic mapping reveals Hudson River sediment processes and habitats, EOS 86(24), pp
- Nitsche et al., 2005, A seabed classification approach based on multiple acoustic sensors in the Hudson River Estuary, in D.M. FitzGerald and J. Knight (editors) High Resolution Morphodynamics and Sedimentary Evolution of Estuaries: Springer, pp 33-55..
- Nitsche et al., 2006, Regional patterns and local variations of sediment distribution in the Hudson River Estuary, Estuarine Coastal and Shelf Science
- Pekar et al., 2004, Estuarine processes and their stratigraphic record: paleosalinity and sedimentation changes in the Hudson Estuary (North America), Marine Geology, 209(1-4): 113-129.
- Slagle et al., 2006, Late-stage estuary infilling controlled by limited accommodation space in the Hudson River. Marine Geology, in press.
- Strayer et al., 2006, Using geophysical information to define benthic habitats in a large river, Freshwater Biology 51, 25?38

Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 1998

Ending_Date: 2003

Currentness_Reference: publication date

Status:

Progress: Complete

Maintenance_and_Update_Frequency: None planned

Spatial_Domain:

Bounding_Coordinates:

West_Bounding_Coordinate: -74.10

East_Bounding_Coordinate: -73.68

North_Bounding_Coordinate: 42.75

South_Bounding_Coordinate: 40.60

Keywords:

Theme:

Theme_Keyword_Thesaurus: none

Theme_Keyword: sidescan

Theme_Keyword: Hudson River Estuary

Theme_Keyword: benthic

Theme_Keyword: remote sensing

Access_Constraints: no constraints

Use_Constraints:

none; Lamont-Doherty Earth Observatory of Columbia University requests to be acknowledged as the originator of the data in future products or derivative research.

Point_of_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: John Ladd

Contact_Organization: Hudson River National Estuarine Research Reserve, NYS DEC

Contact_Address:

Address_Type: mailing and physical address

Address: Norrie Point Environmental Center

City: Staatsburg

State_or_Province: New York

Postal_Code: 12580

Country: USA

Contact_Voice_Telephone: 845-889-4745

Contact_Electronic_Mail_Address: jxladd@gw.dec.state.ny.us

Data_Set_Credit:

Robin Bell, William Ryan, Suzanne Carbotte, Frank Nitsche, Lamont-Doherty Earth Observatory of Columbia University

Native_Data_Set_Environment: Microsoft Windows 2000

Cross_Reference:

Citation_Information:

Originator: Lamont-Doherty Earth Observatory of Columbia University

Publication_Date: 2005

Title: Hudson River Estuary benthic survey index

Series_Information:

Series_Name: Hudson River Estuary Program

Issue_Identification: benthic mapping project

Publication_Information:

Publication_Place: Albany, NY

Publisher: NYS DEC

Cross_Reference:

Citation_Information:

Originator: Lamont-Doherty Earth Observatory of Columbia University

Publication_Date: 2005

Title:

Hudson River Estuary Sidescan and Seismic Track Line Information

Series_Information:

Series_Name: Hudson River Estuary Program

Issue_Identification: Benthic Mapping Project

Publication_Information:

Publication_Place: Albany, NY

Publisher: NYS Dept Environmental Conservation

Data_Quality_Information:

Attribute_Accuracy:

Attribute_Accuracy_Report:

All data samples were taken using DGPS positioning with a horizontal accuracy is +/- 1 m. Quality - Data quality was in general excellent. Field conditions which introduced noise into the sidescan data included stratification of the water column in shallow water during calm, hot days, excessive ship's motion, turbulent water due to boat wakes, and sonar fish vibration due to build up of vegetation on the towing cable.

Logical_Consistency_Report:

After each day of acquisition the data was returned to Lamont-Doherty Earth Observatory (LDEO) for overnight quality control. For the side-scan data the goal was to ensure the proper number of bits were present in the data, that the navigation and time tagging was appropriate and that the preliminary imagery was correct. The goal was to identify any corrupt track while it was still possible to re-shoot the data. The side-scan quality control for each track included a page of text containing the critical acquisition parameters and a track plot of both the 100 and 384 kHz data. The track plot included an overlay of the ships heading and depth from the single beam. These products were reviewed by a project scientist early the next day. Summaries of the quality control results were transmitted to the field crew to enable acquisition of repeat data as necessary.

Completeness_Report:

The data covers 90% of the Hudson River Estuary from Verrazano Narrows to Troy. Areas not covered include some broad shallow banks and areas behind islands.

Lineage:

Process_Step:

Process_Description:

NAVIGATION GPS navigation data were acquired from a pair of Ashtech Z-12 (dual-frequency 12-channel Y-Code) geodetic-quality GPS receivers, operated continuously at 2 Hz. One receiver was located on the ship and one was located at a fixed basestation at LDEO. The GPS data are post-processed with the KARS (Kinematic and Rapid Static) software package developed by G.Mader at the National Geodetic Survey (NGS). We solve for the relative position of the ship at each epoch with respect to the fixed basestation, which has been precisely located from a static solution with nearby stations in the CORS (Continuously Operated Reference Stations) network, and precise satellite orbit data obtained from the Crustal Dynamics Data Information System (CDDIS) archive. Differential processing allows us to remove clock errors and orbit errors which are common to both receivers. The tropospheric delay is modeled, and the ionospheric error is reduced by using both the L1 and L2 frequency observables. KARS uses an optimized integer-search algorithm to resolve initial satellite ambiguities and detect cycle slips. Final pseudorange corrected positions are accurate to 0.5 meters.

Process_Date:

1998 to 2004 (real time: see Begin_date/End_date in track lines attribute table)

Process_Step:

Process_Description:

ACQUISITION Towed Equipment - The towed side-scan system used for this program was the Edge Tech DF-1000 dual frequency sonar with an ISIS data acquisition topside. The system is designed to acquire data at two frequencies 100 kHz and 384 kHz. The six foot tow fish was deployed from a boom off the bow of the ship to place the system in quiet water for optimal instrument performance. The fish was towed at a depth of 1.5 m. The fish has transducers and receivers on either side of the tow fish. The transducers transmit and receive both frequencies simultaneously. The acoustic signals are digitized in the tow fish and transmitted with a high-speed digital uplink to the onboard acquisition system. The tow cable is a single coaxial cable. A swath width of 200 m to each side was used so that together a total width of 400 m of riverbed was surveyed with a single survey track.
Topside Equipment - The topside unit was an ISIS data acquisition supported by Triton Elic. The side-scan data was time tagged in the ISIS system and recorded to hard disk. The Triton Elic system also recorded several auxiliary data streams including: the ship's compass heading, the single-beam bathymetry and the real time navigation. The LDEO ship compass was mounted in magnetically quiet location of the boat. The navigation data recorded in the ISIS system was differential GPS positions received by a Trimble AG-132 unit.

Process_Date:

1998 to 2004 (real time: see Begin_date/End_date in track lines attribute table)

Process_Step:

Process_Description:

POST ACQUISITION PROCESSING The processing included demultiplexing of raw data, correcting for layback and merging track data to produce final mosaics. Demultiplexing -The raw data files recorded with the ISIS system contain both frequencies and data from the different serial channels. In a first step both frequencies and the additional data were split into separate files. The data values were converted into a range of 0 (high-backscatter) to 255 (low- backscatter). Correction for Laybacks - The corrections for layback, i.e. the difference between GPS antenna position and the position of the side-scan fish, was calculated as part of the navigation processing. The corrected navigation is merged with the side-scan data. Merging Track Data - We have chosen the philosophy of providing minimally processed backscatter data in the final mosaics. This ensured the preservation of the maximum information. We have implemented a slant range correction for the data. All the mosaicing routines assume a flat bottom. The major corrections incorporated into the mosaicing routine are the removal of the nadir and to systematically seam the data. The nadir central stripe produces a final product which is difficult to interpret. Our survey design ensured that the nadir from one line could be filled with the outer beam data from the adjacent line. In the mosaic we have filled the nadir with the adjacent line data wherever possible. We evaluated in detail the utility of correcting the side-scan sonar for the heading of the fish, which can differ from the heading of the boat. We concluded that an empirically derived correction of 0°-10° depending on area (i.e. areas with strong currents like the highlands needed a larger correction) reduced the swath to swath mismatch of riverbed features and improved the final mosaic. Generate Final Images - Mosaics were generated at 2 m and 1 m pixel resolution for 5? tiles of the river representing 5 nautical miles. For each tile four mosaics were produced using different azimuth and different frequency data. These four mosaics are a north-south 100 kHz mosaics, an east-west 100 kHz mosaic, a north-south 384 kHz mosaic and an east-west 384 kHz mosaic.

Process_Date: 2004

Spatial_Data_Organization_Information:

Indirect_Spatial_Reference:

The naming convention for mosaic panels is as follows: the first two characters (letter and digit) refer to a survey area as defined in the Hudson River Estuary Benthic Survey Index (see Cross_Reference above). The third character ("n" or "w") designates the orientation of the track line along which the sonar data was collected (see Hudson River Estuary Sidescan and Seismic Track Line Information) (see Cross_Reference above) (in much of the estuary data was collected along north-south track and east-west track). The ?100? refers to 100 KHz, the dominant frequency of this dataset (sidescan sonar was also acquired at 384 KHz). ?2m? refers to 2-meter pixel resolution (data was also mosaiced with one-meter pixels). Some of the survey areas were broken into northern and southern subsections; hence the final part of the file name. The exceptions are as follows: the NY/NJ Harbor survey that was only surveyed along east-west tracks but was surveyed once in 2002 and again in 2003; survey index areas B8 and B9 were not surveyed along east-west tracks.

Direct_Spatial_Reference_Method: Raster

Raster_Object_Information:

Raster_Object_Type: pixel

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: 1

Ordinate_Resolution: 1

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: sidescan mosaics

Entity_Type_Definition: sidescan images from the Hudson River Estuary

Entity_Type_Definition_Source: Lamont-Doherty Earth Observatory of Columbia University

Attribute:

Attribute_Label: Value

Attribute_Definition:

value is backscatter with 0=high backscatter and 255=low backscatter. The native 16-bit output from the system is normalized to 8-bit grey scale values.

Attribute_Definition_Source: Lamont-Doherty Earth Observatory of Columbia University

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0

Range_Domain_Maximum: 255

Distribution_Information:

Distributor:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: New York State Department of Environmental Conservation

Contact_Person: John Ladd

Contact_Position: Benthic Mapping Coordinator

Contact_Address:

Address_Type: mailing and physical address

Address: Norrie Point Environmental Center

City: Staatsburg

State_or_Province: New York

Postal_Code: 12580

Country: USA

Contact_Voice_Telephone: 845-889-4745

Contact_Electronic_Mail_Address: jxladd@gw.dec.state.ny.us

Distribution_Liability:

New York State Department of Environmental Conservation provides these geographic data "as is." New York State Department of Environmental Conservation makes no guarantee or warranty concerning the accuracy of information contained in the geographic data. New York State DEC further makes no warranty, either expressed or implied, regarding the condition of the product or its fitness for any particular purpose. The burden for determining fitness for use lies entirely with the user. Although these data have been processed successfully on a computer system at New York State Department of Environmental Conservation, no warranty expressed or implied is made regarding the accuracy or utility of the data on any other system or 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. It is strongly recommended that careful attention be paid to the contents of the metadata file associated with these data. New York State Department of Environmental Conservation shall not be held liable for improper or incorrect use of the data described and/or contained herein.

Metadata_Reference_Information:

Metadata_Date: 20080101

Metadata_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: Lamont-Doherty Earth Observatory of Columbia University.

Contact_Person: Dr. Robin Bell

Contact_Address:

Address_Type: mailing and physical address

Address: 61 Route 9W

City: Palisades

State_or_Province: NY

Postal_Code: 10964-8000

Contact_Voice_Telephone: 845-365-8827

Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata

Metadata_Standard_Version: FGDC-STD-001-1998