U.S. Geological Survey
2017
Digital Elevation Model from Single-Beam Bathymetry XYZ Data Collected in 2015 from Raccoon Point to Point Au Fer, Louisiana
raster digital data
http://pubs.usgs.gov/ds/1041/downloads/Raster/PAF_200m_DEM.zip
Chelsea A. Stalk
Nancy T. DeWitt
Jack L. Kindinger
James G. Flocks
Billy J. Reynolds
Kyle W. Kelso
Jake J. Fredericks
Thomas M. Tuten
2017
Coastal Single-Beam Bathymetry Data Collected in 2015 from Raccoon Point to Point Au Fer, Louisiana
multimedia presentation
U.S. Geological Survey Data Series
1041
St. Petersburg, FL
U.S. Geological Survey
https://doi.org/10.3133/ds1041
As part of the Barrier Island Comprehensive Monitoring Program (BICM), scientists from the U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center conducted a nearshore single-beam bathymetry survey along the south-central coast of Louisiana, from Raccoon Point to Point Au Fer Island, in July 2015. The goal of the BICM program is to provide long-term data on Louisiana’s coastline and use this data to plan, design, evaluate, and maintain current and future barrier island restoration projects. The data described in this report will provide baseline bathymetric information for future research investigating island evolution, sediment transport, and recent and long term geomorphic change, and will support modeling of future changes in response to restoration and storm impacts. The survey area encompasses more than 300 square kilometers (km2) of nearshore environment from Raccoon Point to Point Au Fer Island. This data series serves as an archive of processed single-beam bathymetry data, collected from July 22–29, 2015, under USGS Field Activity Number 2015-320-FA. Geographic information system data products include a 200-meter-cell-size interpolated bathymetry grid, trackline maps, and point data files.
This 200-meter-cell-size digital elevation model is an interpretive product that was derived from the processed single-beam bathymetry data collected in July 2015 along the south-central coast of Louisiana.
This dataset serves as a comprehensive archive for the final Digital Elevation Model (DEM) created by the use of all single-beam bathymetry data collected under the FAN (2015-320-FA), which encompasses data from four separate survey platforms; the Research Vessel (R/V) Sallenger (15BIM05), R/V Jabba Jaw (15BIM06), R/V Shark (15BIM07), and R/V Chum (15BIM08). The single-beam bathymetry corrected Global Positioning System (GPS) data was obtained through post processing of the base station data to the concurrent rover data. All datasets were transformed from their initial datum International Terrestrial Reference Frame of 2000 (ITRF00) to the North American Datum of 1983 (NAD93) (CORS 96), using the geoid model of 2012A (GEOID12A) (National Oceanic and Atmospheric Administration National Geodetic Survey [NOAA NGS] VDatum software 3.2; http://vdatum.noaa.gov/). The final x,y,z position point data were gridded at a 200-meter-cell-size resolution to create the digital elevation model that represents elevations from -0.40 to -7.25 meters.
20150722
20150729
ground condition
none
-91.39248661
-90.84475369
29.33329727
29.05684946
USGS Metadata Identifier
USGS:135a829b-9589-43a9-b74a-d9b25a18d6f1
ISO 19115 Topic Category
elevation
geoscientific Information
imageryBaseMapsEarthCover
oceans
USGS Thesaurus
marine geology
bathymetry
geophysics
General
single-beam
CARIS
HIPS and SIPS
hydrography
geophysical
U.S. Geological Survey
USGS
Coastal and Marine Geology Program
CMGP
St. Petersburg Coastal and Marine Science Center
SPCMSC
Coastal Change and Transport
Single-beam Bathymetry
2015-320-FA
digital elevation model
Geographic Names Information System (GNIS)
South Central Coast
Gulf of Mexico
Point Au Fer
Raccoon Island
Louisiana
None
The U.S. Geological Survey requests that it be referenced as the originator of this dataset in any future products or research derived from these data. These data should not be used for navigational purposes.
Cherokee Nation Technologies/U.S. Geological Survey
Chelsea A. Stalk
Researcher I
Mailing and physical
600 4th Street South
St. Petersburg
FL
33701
USA
(727) 502-8000
cstalk@usgs.gov
U.S. Geological Survey, Coastal and Marine Geology Program, St. Petersburg Coastal and Marine Science Center (SPCMSC)
Microsoft Windows 7 Service Pack 1; Esri ArcGIS 10.2 Service Pack 1 Build 3143; Esri ArcCatalog 10.2 Build 3143
The accuracy of the data is determined during data collection. Methods are employed to maintain data collection consistency aboard various platforms. During mobilization, each piece of equipment is isolated to obtain internal and external offset measurements with respect to the survey platform. All the critical measurements are recorded manually and digitally entered into their respective programs for calibration, acquisition, and post processing. Each system has a dedicated computer, and efforts are made to utilize the same equipment and software versions on all systems. However, upgrades and changes occur and require additional setup, measurements, and notation. Differential Global Positioning System (DGPS) is always implemented for navigational accuracy as a post-processing step. These bathymetric data have not been independently verified for accuracy, rather verified as a whole product.
The single-beam bathymetry data were collected during one research cruise in July, 2015 (2015-320-FA). Refer to the online Data Series linkage for field logs, vessel platform descriptions, and other survey information. This dataset was created to provide a post-processed bathymetric grid from the data and accompanying x,y,z deliverables. The DEM is 200-meter-cell-size resolution; data gaps between acquisition tracklines are predicted values generated by the gridding algorithm - "natural neighbors".
This is a completely processed bathymetric DEM representing an interpolated bathymetric surface derived from final single-beam bathymetry data.
The stated horizontal accuracy of the Ashtech Proflex 500 and 800 GPS receivers used during single-beam bathymetry acquisition is reported by the service as +/-10 mm for kinematic surveying.
-0.00000134 to +0.00000134
latitude decimal degrees
-0.0000019 to +0.0000019
longitude decimal degrees
The stated vertical accuracy of the Ashtech Proflex 500 and 800 GPS units used during single-beam bathymetry acquisition is +/- 10 mm. The Teledyne TSS-DMS-05 MRU, which integrates the DGPS position with motion, proposes accuracy of roll and pitch (+/- 0.05 degrees), and heave (5% of heave amplitude or 5 cm). The vertical accuracy for the Odom Echotrac-CV100 unit used on all survey platforms is 0.01 m +/- 0.1% of the depth value.
DGPS Navigation Processing:The GPS base stations were established by USGS personnel for the purpose of this survey. Benchmark PAF1 was located to the east of the survey area on a marsh island to the west of Fish Bayou, PAF2 was located in the middle of the survey area on the eastern shore of Oyster Bayou, and PAF3 was located in the western portion of the survey on the middle shore of Point Au Fer Island (http://pubs,usgs.gov/ds/01041/html/ds1041_overview.html). The base stations were equipped with Ashtech Proflex GPS Receivers recording 12-channel full-carrier-phase positioning signals (L1/L2) from satellites via Thales choke-ring antennas, recording at a rate of 0.1 seconds (s). GPS instrumentation was duplicated on all survey vessels (rovers) with the exception of the R/V Shark (15BIM07) and the R/V Chum (15BIM08) on which Ashtech Global Navigation Satellite Systems (GNSS) were used instead of Choke-ring antennas. The base receivers and rover receivers recorded positions concurrently at all times throughout the survey. Rovers R/V Shark and R/V Chum recorded at 0.1 s throughout the survey while the R/V Jabba Jaw and the R/V Sallenger recoded at 0.2 s. The coordinate values for each of the GPS base stations (PAF1, PAF2, PAF3) are the time-weighted average of values obtained from the National Geodetic Survey's On-Line Positioning User Service (OPUS). All base station sessions of recorded data are decimated to 30 s, and then submitted to OPUS via the online service. All solutions are then returned to the user and entered into a spreadsheet where time-weighted ellipsoid values are calculated for each station, for the entire occupation. Any individual ellipsoid value that falls outside three standard deviations for the entire occupation was excluded and the final coordinate values were then determined. The final base station coordinates were imported into GrafNav version 8.5 (Waypoint Product Group) and the kinematic GPS data from the survey vessel were post-processed to the concurrent GPS data from the base stations. In all cases the closest base station to the roving vessel was utilized to help keep vertical error to a minimum. During processing, steps were taken to ensure that the trajectories between the base and rover were clean and resulted in fixed positions. By analyzing the graphs, trajectory maps, and processing logs that GrafNav produces for each GPS session, GPS data from satellites flagged by the program as having poor health or satellite time segments with cycle slips were excluded, and the satellite elevation mask angle was adjusted to improve the position solutions when necessary. The final, differentially-corrected, precise DGPS positions were computed at their respective time intervals (0.2 s for 15BIM05, 15BIM06 and 0.1 s for 15BIM07, 15BIM08), and then exported in ASCII text format. The file was then used to replace the uncorrected real-time rover positions recorded during acquisition. The GPS data were processed and exported in the World Geodetic System of 1984 (WGS84) (G1150) geodetic datum UTM zone 15N.
2015
Cherokee Nation Technologies/U.S. Geological Survey
Chlesea A. Stalk
Researcher I
mailing and physical
600 4th Street South
St. Petersburg
FL
33701
USA
(727) 502-8000
cstalk@usgs.gov
Single Bream Processing: The raw HYPACK® data files were imported into CARIS Hydrographic Information Processing System (HIPS) and Sonar Information Processing System (SIPS) ® version 9.0.17. The corrected DGPS positions exported from GrafNav were imported into CARIS using the generic data parser tool. After parsing, the navigation data were scanned using the Navigation Editor, which allows the user to view multiple types of plots including trackline orientation, timing, and course direction. This check verifies if the parsed data corresponds to the processed DGPS. Next, Speed of Sound Profile (SVP) casts were entered, and edited, using the SVP editor tool, and then applied as nearest in distance within time. All soundings are referenced to the WGS84 ellipsoid during processing. This involved a step in CARIS to compute the GPS tide. The GPS tide represents the ellipsoidal surface. GPS tide and GPS height are then compared against each other to ensure correct computation by the program and applied GPS antenna height provided in the vessel file. All bathymetric data components; position, motion, depth, GPS tide, and Speed of Sound (SOS), were then merged and geometrically corrected in CARIS to produce processed x,y,z point data. Once merged, the dataset is reviewed for erroneous points using the Single Beam Editor. The points that are visually obvious outliers are often related to cavitation in the water column obscuring the fathometer signal, tight turns in the surf zone affecting the tracking of the incoming GPS signal, and/or false readings due to general equipment issues. Data showing these are either discarded or adjusted to surrounding sounding depths. Also, data points in areas of extremely shallow water (0.30 m to 0.50 m) such as on shoals or within seagrass beds were reviewed against the surrounding data for overall consistency. Finally, a Bathymetry with Associated Statistical Error (BASE) surface was created. Using the Subset Editor, the BASE surface was used as a color coded guide to pinpoint crossings that are visually offset from one another. If an offset was identified, it was further examined and was reprocessed if necessary. The geometrically-corrected point data are then exported as an x,y,z ASCII text file referenced to WGS84 (G1150), equivalent to ITRF00, UTM 15, and ellipsoid height in meters. The single-beam bathymetry datasets combined (15BIM05, 15BIM06, 15BIM07, and 15BIM08) consists of 4,626,476 x,y,z data points with an ellipsoidal height range of -35.096 m to -25.904 m.
2015
15BIM05_SBB_02_1041_ITRF00.txt
15BIM06_SBB_02_1041_ITRF00.txt
15BIM07_SBB_02_1041_ITRF00.txt
15BIM08_SBB_02_1041_ITRF00.txt
Cherokee Nation Technologies/U.S. Geological Survey
Cheslea A. Stalk
Researcher I
mailing and physical
600 4th Street South
St. Petersburg
FL
33701
USA
(727) 502-8000
cstalk@usgs.gov
Quality Control and Quality Assurance (QA/QC) and Datum transformation: All single-beam data found in the ASCII exported from CARIS were imported into Esri ArcMap version 10.2, where a shapefile of the individual data points (x,y,z) was created and plotted in 0.5-m color coded intervals. First, all data were visually scanned for any obvious outliers or problems. Then, the data were run through an in-house script similar to a Python script. The script was created for the purpose of evaluating elevation differences at the intersection of crossing tracklines by calculating the elevation difference between points at each intersection using an inverse distance weighting equation. Elevation values at line crossings should not differ by more than the combined instrument acquisition error (per manufacturer specified accuracies). GPS cycle slips, stormy weather conditions, and rough sea surface states can contribute to poor data quality. If discrepancies that exceed the acceptable error threshold were found, then the line in error was either removed or statically adjusted only by the average of the crossings within the line. The script was run on all vessel point data first on a vessel by vessel basis and then run a final time for all data points from all vessels collectively by use of a merged shape file with all point data (2015-320-FA_SBB_Level_04_1041_ITRF00). For this dataset, the collective run is the most important as the survey structure did not allow for sufficient vessel crossing, rather vessels crossing other vessels. Once the dataset passed all QA/QC procedures and manual editing steps, the data were considered final, pending datum adjustments. The single-beam bathymetric data were transformed horizontally and vertically (via the transformation software VDatum version 3.2) from their data acquisition datum WGS84 (ITRF00) to the NAD83 CORS96 reference frame using the NGS GEOID12A. The NAD83 x,y,z data points were exported in ASCII.
2015-320-FA_SBB_Level_03_1041_ITRF00.txt
2015
15BIM05_SBB_NAD83_UTM15N_NAVD88_GEOID12A.txt
15BIM06_SBB_NAD83_UTM15N_NAVD88_GEOID12A.txt
15BIM07_SBB_NAD83_UTM15N_NAVD88_GEOID12A.txt
15BIM08_SBB_NAD83_UTM15N_NAVD88_GEOID12A.txt
Cherokee Nation Technologies/U.S. Geological Survey
Chelsea A. Stalk
Researcher I
mailing and physical
600 4th Street South
St. Petersburg
FL
33701
USA
(727) 502-8000
cstalk@usgs.gov
Gridding Bathymetric data and computing grid error: The single-beam soundings were imported into Esri’s ArcMap version 10.2 and gridded using Spatial Analyst tools "create tin," "tin to raster," and "extract by raster mask." First, a bounding polygon representing the extent of survey tracklines was created and converted into a raster mask using the ArcGIS "polygon to raster" tool. Next, the final point data were merged into a single shapefile and converted into a triangulated irregular network (TIN), using the "create tin" tool and then the data were converted into a raster DEM by use of the "Tin to raster" tool using the natural neighbor function with a cell size of 200 m. Finally, the interpolated DEM is clipped to the survey extent utilizing the "extract by mask" tool and using the raster mask created in the first step of this process. The final product is a DEM of the entire survey extent, with grid elevation values ranging from -0.40 m to -7.25 m. In order to evaluate how well the final DEM represents the final sounding data both spatially and quantitatively, a comparison of the DEM versus the sounding (x,y,z point) data was plotted in ArcGIS by use of the “Extract values by points” spatial analyst tool. This tool extracts the value represented by the underlying grid and compares it to that of the overlying point data. By use of the generated shape file and associated attribute table, the root mean square (RMS) error, quantified as the difference between the measured depth and the grid depth values, and calculated. The overall RMS Error in meters is 0.16.
2015_320_FA_SBB_NAD83_UTM15N_NAVD88_GEOID12A.txt
2015
PAF_200m_DEM1.tif
Cherokee Nation Technologies/U.S. Geological Survey
Chelsea A. Stalk
Researcher I
mailing and physical
600 4th Street South
St. Petersburg
FL
33701
USA
(727) 502-8000
cstalk@usgs.gov
Added keywords section with USGS persistent identifier as theme keyword.
20201013
U.S. Geological Survey
VeeAnn A. Cross
Marine Geologist
Mailing and Physical
384 Woods Hole Road
Woods Hole
MA
02543-1598
508-548-8700 x2251
508-457-2310
vatnipp@usgs.gov
Raster
Grid Cell
150
265
1
Universal Transverse Mercator
15
0.9996
-93
0.0
500000.0
0.0
row and column
200
200
meter
NAD83 North American Datum 1983
Geoid 12A
6378137.0
298.257222101
North American Vertical Datum 1988 (NAVD88)
0.10
meter
Implicit coordinate
Cherokee Nation Technologies/U.S. Geological Survey
Chelsea A. Stalk
Researcher I
mailing and physical
600 4th Street South
St. Petersburg
FL
33701
USA
(727) 502-8000
cstalk@usgs.gov
PAF_200m_DEM1.tif
This publication was prepared by an agency of the United States Government. Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made regarding the display or utility of the data on any other system, nor shall the act of distribution imply any such warranty. The U.S. Geological Survey shall not be held liable for improper or incorrect use of the data described and (or) contained herein. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof.
GeoTIFF
ZIP
0.38
http://pubs.usgs.gov/ds/1041/downloads/Raster/PAF_200m_DEM.zip
DVD
112
KB
UDF
none
The raster contained in the .zip file is available as GeoTIFF.
20210922
Cherokee Nation Technologies/U.S. Geological Survey
Chelsea A Stalk
Researcher I
mailing and physical
600 4th Street South
St. Petersburg
FL
33701
USA
727-502-8000
cstalk@usgs.gov
Content Standard for Digital Geospatial Metadata
FGDC-STD-001-1998
Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution.
None
Unclassified
None